Photoshop elements 4 reinstallation problem

[scapa]

Hi, I could really use some help with this problem. I have been using Photoshop Elements 4 for a couple of years on my G4 - Recently the program got corrupted (have no idea why!) and would not open Bridge or recognize raw files. So I uninstalled the program by putting it in the trash, emptying the trash, rebooting, and attempting a new new install from the original CD. But I get an error message that says that "a required file is missing". I searched the Adobe knowledge base and there is no info on this error message. I just don't know what to do to fix this error. Any advice? Thanks so much!
Jane