Running CVI on Windows 95 OS, fopen(filename,"a+") returns access denied if file already exist?

[LostInC]

I have identical CVI code running on different computers. One is running on Windows 98 and the other Windows 95. The code works fine for creating and appending data to files on the computer with Windows 98 but on the system running Windows 95 it will not append. This system may also have Microsoft SMS running in the backround. Has anyone encountered this problem or can suggest a different method for creating and appending data to files.

[LostInC]

Update:
I found that the data file attributes were different between the two systems. For some reason, the code running on Windows 95 is creating the data files as read only while the system running on Windows 98 is not. Also, CVI version 5.0 was used to compile the older code versus CVI version 5.5 for the newer code.