ReportingServicesService hangs up the Server

Something strange has happened with Reporting Services on the server. When the ReportingServicesService windows service is runnig, it loads CPU (up to 100%) and allocates more and more virtual memory (up to 1,5Gb). There aren't subscriptions for the Report Server and nobody permanently executes reports on it. How can I fix that memory leak?

Log during memory leak:
ReportingServicesService!library!4!4/12/2007-15:39:48:: i INFO: Initializing ConnectionType to '0' as specified in Configuration file.
ReportingServicesService!library!4!4/12/2007-15:39:48:: i INFO: Initializing IsSchedulingService to 'True' as specified in Configuration file.
ReportingServicesService!library!4!4/12/2007-15:39:48:: i INFO: Initializing IsNotificationService to 'True' as specified in Configuration file.
ReportingServicesService!library!4!4/12/2007-15:39:48:: i INFO: Initializing IsEventService to 'True' as specified in Configuration file.
ReportingServicesService!library!4!4/12/2007-15:39:48:: i INFO: Initializing PollingInterval to '10' second(s) as specified in Configuration file.
ReportingServicesService!library!4!4/12/2007-15:39:48:: i INFO: Initializing WindowsServiceUseFileShareStorage to 'False' as specified in Configuration file.
ReportingServicesService!library!4!4/12/2007-15:39:48:: i INFO: Initializing MemoryLimit to '60' percent as specified in Configuration file.
ReportingServicesService!library!4!4/12/2007-15:39:48:: i INFO: Initializing RecycleTime to '720' minute(s) as specified in Configuration file.
ReportingServicesService!library!4!4/12/2007-15:39:48:: i INFO: Initializing MaximumMemoryLimit to '80' percent as specified in Configuration file.
ReportingServicesService!library!4!4/12/2007-15:39:48:: i INFO: Initializing MaxAppDomainUnloadTime to '30' minute(s) as specified in Configuration file.
ReportingServicesService!library!4!4/12/2007-15:39:48:: i INFO: Initializing MaxQueueThreads to '0' thread(s) as specified in Configuration file.
ReportingServicesService!library!4!4/12/2007-15:39:48:: i INFO: Initializing IsWebServiceEnabled to 'True' as specified in Configuration file.
ReportingServicesService!library!4!4/12/2007-15:39:48:: i INFO: Initializing MaxActiveReqForOneUser to '20' requests(s) as specified in Configuration file.
ReportingServicesService!library!4!4/12/2007-15:39:48:: i INFO: Initializing MaxScheduleWait to '5' second(s) as specified in Configuration file.
ReportingServicesService!library!4!4/12/2007-15:39:48:: i INFO: Initializing DatabaseQueryTimeout to '120' second(s) as specified in Configuration file.
ReportingServicesService!library!4!4/12/2007-15:39:48:: i INFO: Initializing ProcessRecycleOptions to '0' as specified in Configuration file.
ReportingServicesService!library!4!4/12/2007-15:39:48:: i INFO: Initializing RunningRequestsScavengerCycle to '60' second(s) as specified in Configuration file.
ReportingServicesService!library!4!4/12/2007-15:39:48:: i INFO: Initializing RunningRequestsDbCycle to '60' second(s) as specified in Configuration file.
ReportingServicesService!library!4!4/12/2007-15:39:48:: i INFO: Initializing RunningRequestsAge to '30' second(s) as specified in Configuration file.
ReportingServicesService!library!4!4/12/2007-15:39:48:: i INFO: Initializing CleanupCycleMinutes to '10' minute(s) as specified in Configuration file.
ReportingServicesService!library!4!4/12/2007-15:39:48:: i INFO: Initializing DailyCleanupMinuteOfDay to default value of '120' minutes since midnight because it was not specified in Configuration file.
ReportingServicesService!library!4!4/12/2007-15:39:48:: i INFO: Initializing WatsonFlags to '1064' as specified in Configuration file.
ReportingServicesService!library!4!4/12/2007-15:39:48:: i INFO: Initializing WatsonDumpOnExceptions to 'Microsoft.ReportingServices.Diagnostics.Utilities.InternalCatalogException,Microsoft.ReportingServices.Modeling.InternalModelingException' as specified in Configuration file.
ReportingServicesService!library!4!4/12/2007-15:39:48:: i INFO: Initializing WatsonDumpExcludeIfContainsExceptions to 'System.Data.SqlClient.SqlException,System.Threading.ThreadAbortException' as specified in Configuration file.
ReportingServicesService!library!4!4/12/2007-15:39:48:: i INFO: Initializing SecureConnectionLevel to '0' as specified in Configuration file.
ReportingServicesService!library!4!4/12/2007-15:39:48:: i INFO: Initializing DisplayErrorLink to 'True' as specified in Configuration file.
ReportingServicesService!library!4!4/12/2007-15:39:48:: i INFO: Initializing WebServiceUseFileShareStorage to 'False' as specified in Configuration file.
ReportingServicesService!servicecontroller!9!4/12/2007-15:39:49:: Total Physical memory: 3220504576
ReportingServicesService!servicecontroller!4!4/12/2007-15:39:49:: i INFO: RPC Server started. Endpoint name ='ReportingServices$MSSQL.3'
ReportingServicesService!library!a!4/12/2007-15:39:49:: i INFO: Catalog SQL Server Edition = Enterprise
ReportingServicesService!resourceutilities!a!4/12/2007-15:39:49:: i INFO: Reporting Services starting SKU: Enterprise
ReportingServicesService!resourceutilities!a!4/12/2007-15:39:49:: i INFO: Evaluation copy: 0 days left
ReportingServicesService!crypto!a!4/12/2007-15:42:46:: i INFO: Initializing crypto as user: NT AUTHORITY\SYSTEM
ReportingServicesService!crypto!a!4/12/2007-15:42:46:: i INFO: Exporting public key
ReportingServicesService!crypto!a!4/12/2007-15:42:47:: i INFO: Performing sku validation
ReportingServicesService!crypto!a!4/12/2007-15:42:52:: i INFO: Importing existing encryption key
ReportingServicesService!servicecontroller!1b!4/12/2007-15:45:46:: i INFO: RPC Server stopped
ReportingServicesService!servicecontroller!1b!4/12/2007-15:46:06:: Can't unload domain, trying again
ReportingServicesService!servicecontroller!1b!4/12/2007-15:46:23:: Can't unload domain, trying again
ReportingServicesService!servicecontroller!1b!4/12/2007-15:46:39:: Can't unload domain, trying again
ReportingServicesService!servicecontroller!1b!4/12/2007-15:46:56:: Can't unload domain, trying again
ReportingServicesService!servicecontroller!1b!4/12/2007-15:47:13:: Can't unload domain, trying again
ReportingServicesService!servicecontroller!1b!4/12/2007-15:47:29:: Can't unload domain, trying again
ReportingServicesService!servicecontroller!1b!4/12/2007-15:47:46:: Can't unload domain, trying again

I have the same problem. Reporting Services 2005 used up to 1.5GB of memory on my dev server. The reports are not big, no more than 500 records. Sometimes memory can ramp up as much as .5 G when running a single report. Once the memory is consumed it doens't get released unless I reboot the machine. What can we do to addresss this problem?