Excel 2010 x64 Compile Error While Opening XLS Which Uses 32-bits LIb

Just opened a Excel Sheet (Created with Excel 2003) in my 64-bit version of Excel 2010 (beta) and received the following error : Compile Error : The code in this project must be updated for use on 64-bit systems. Please review and update Declare statements and then mark them with the Ptrsafe attribute.
I never received such an error (maybe because Excel 2010 is the first 64-bit Excel?), so I started to feed Google a part of the error message. The first hit brought me the solution.

So I added the PtrSafe attribute to the Declare function which changed the lines in this : Declare PtrSafe Function….. After I saved the sheet, closed it and reopened it again..the error just disappeared!