@darkf0x
Yes, the workaround is a very dangerous workaround. Just as RAGS doesn't handle international delimiters properly, I'm sure a number of other software that isn't a major commercial release specifically designed to work with changing delimiters will be prone to problems.
Truthfully, I wouldn't even recommend the suggested fix even on a temporary basis. I actually change the region my computer is set to (to one that uses the alternate delimiters) rather than changing a single delimiter within the active region (I still make sure to change it back as soon as I'm done playing, but this is at least a marginally safer change for well coded programs).
@LRM
I wouldn't expect that to solve all the problems. Some of the numbers are likely corrupted before the save, so the saved number is actually wrong (completely wrong, not just wrong delimiter... say the game means to add 1 + 1 but instead does 1,000 + 1.000 as it has a number in each format. Regardless of which format is deemed correct, this becomes 1001 instead of 2. Then save the game. No matter what you do, there is no way to turn that 1001 back into a 2). There are other ways of possible corruption as well. Without diving into the code it's tough to give accurate predictions. Depends on how RAGS is coded as well as how this specific game is coded.
As I said before, what you suggest may work reasonably well, but it isn't an option I'd be willing to wager any money on.