runtime error in DLL containing ClearWin code

I am calling a DLL (compiled with FTN95, contains a lot of calculations) from an Excel spreadsheet, and this works fine. However, I decided to display a window at the start of the main fortran routine, with info about the version, contact, author, etc., using a fomat window.

When the spreadsheet is loaded, the first call to the DLL works fine, displaying the window and doing the calculations. However, the second call shows a runtime error window, with the following message:

unable to register class SalfordDialog.

Pressing OK then closes the spreadsheet.

Any idea what is wrong with this approach?

Roger

I do not know why this happens but you may be able to avoid the problem by finding a way to call the Windows API function LoadLibrary in order to keep salflibc.dll loaded. You should also call FreeLibrary afterwards.

Done what you suggested, and it is running correctly now.

Many thanks for your help

Roger