Reporting error message as "something like..." isn't very helpful!

The likely source of the problem is that the third parameter to RasSetEntryProperties is a RASENTRY structure. And this structure gained some new fields as of NT 5.00 (Win2K) and a few more as of NT 5.01. If the module has not been updated since 2000 and hasn't been modified for use with version later than 4.x, then it is quite probable that the structure the module is passing does not have these new fields, and when your OS attempts to access those new fields, it segfaults.

There is no need to discard the module completely, you only need to update the structure that is being passed for parameter 3 (and check the others). You'll need the same information either way, and there's little point in throwing the baby out with the bathwater:)

A couple of links to get you started.

RasSetEntryProperties and RASENTRY struct