ReportServer Project

I am getting the following problem when I try to build the ReportServer Project:-- Build started: Project: Report Project9, Configuration: Debug Error: Value cannot be null.========== Build: 0 succeeded or up-to-date, 1 failed, 0 skipped ==================== Deploy: 0 succeeded, 0 failed, 0 skipped ==========--But in the report preview, report display correctly. Plz. suggest me what should i have to do.

http://forums.microsoft.com/MSDN/ShowPost.aspx?PostID=327150&SiteID=1

http://forums.asp.net/p/980185/1254341.aspx#1254341

It could be any number of things. Can you provide more specifics?