Building shows warning cs0472, but I don't see this warning when building with VS 2010

I have the following warning:

"C:\TeamCity\buildAgent\temp\buildTmp\.NETFramework,Version=v4.0.AssemblyAttributes.cs" [10:48:33]: [Csc] Services\External\ColorService.cs(762, 74): warning CS0472: The result of the expression is always 'false' since a value of type 'decimal' is never equal to 'null' of type 'decimal?'

However, I can't pinpoint this error or why it is happening because I don' t have 762 lines in ColorService.cs  It only has 93 lines.  I also can't find anywhere where checking if decimal == null, so why is TeamCity displaying this warning?