Sketchup not cooperating

[edmonton_stinks 5]

Hey Simtropolis, it's been a while. I've been away without my trusty SC4 disk, so I haven't contributed a whole lot lately. I'm currently working on a project where Sketchup is required, but it's not installing. Every time I try to install it, I get this nifty little error message, usually as it's just nearing completion.

I haven't had a lot of success attempting to resolve this myself, and I'll likely need Sketchup a lot in the future as my design professor seems to like it, so if anyone's ever gotten this message before I'd appreciate a little insight.