Compatibility issues with 2010 and 2007

I've been writing a macro for someone else in our office, but she uses 2007 and 2010. I didn't think it would be an issue with this macro because it is fairly simple and it doesn't work with any other applications, just excel. What is supposed to happen is that when I enter in someone's name into a chart and some rgb values with it, the macro will take those and create a conditional formatting rule on a different table so whenever someone's name pops up on it, the row changes into whatever color is associated with that name. It works great on my computer, but when I try to use it on hers, it messes up big time. I tried it on some other people's computers (both 2007 and 2010) and it worked on the 2010's but not the 2007's, so I know it is an issue between the versions. I then narrowed it down to the line where the issue occurs. What is supposed to happen on this line is that the macro will create the conditional formatting rule with a formula. However, when it creates the formula, instead of entering $C1, it enters $C1048549 (or some other weird number), and I have no idea why.

I've included pictures of the highlighted line of code where the issue occurs, a picture of what happens on 2010 when it works, and what happens on 2007 when it doesn't.

Thanks for helping, I'm really stuck on this