We have a DLL which has been running solid for years. We had to modify a function in one part of the DLL and now an unrelated function is throwing the above error when we attempt to:

Code:
intFileNum = FreeFile()
Open strFileName For Binary Access Read As #intFileNum
Suddenly, this part of the DLL can't open the file. Other than the unrelated function, nothing has changed. Have checked permissions, no change to the network or servers, the file it is attempting to open exists and can be opened from the Start -> Run menu item in Windows. I have tried changing the function signature by adding an optional parameter, have unregistered and re-registered the DLL...everything I can possibly think of, I have tried. I'm out of ideas. Does anybody have suggestions of why this has suddenly gone bad for me?

Thanks for reading this,
Mike