VS 2005 error in VB6 application

Hi,

I use winforms (VB6) app and got an error (Run-time error '91': Object variable or With block variable not set) each time I try to start this app and Visual Studio 2005 is already opened. Since I dont have same issue when using VS2010 I guess problem is with VS2005. Any advice or solution?

Thanks.

EDIT: Just forget to mention same thing happens if I try to use app and have SQL Server 2008 management studio open.