When I run RMXP on Vista it gives me a lot of errors but I ran around it. First it complained that I didn't have RGSS102E.dll but I did, then I had to install the RTP, and afterwards it gave me an error saying I was using the wrong version, so I opened the project in notepad and changed the version to my current version (1.01) and then after that it still gave me problems so what I did was I opened the Game.ini in notepad and changed the line where it said RGSS102E.dll to RGSS100J.dll
I always run my older programs on compatibility for WindowsXP service pack 2 and as administrator anyways.
And now it works a-ok! :D
The only downside is EVERYTIME I save the project it overwrites the Game.ini and I have to either copy-paste the good one or change it myself so it says RGSS100J.dll in there ^^
I thought I would share this information since I checked on other forums and a lot of people had similar Vista related problems that I did. I hope this might help some people if they ever wondered, if not, then it's another problem.
^^