If you decide to move to Audition CC (and, depending on your needs, the software has "grown up" quite a bit) I can vouch for that software Charles has linked to. I was written by a regular in these forums (Suitespot) so support is excellent! One thing to note is that you have to be running a 64 bit operating system.
The problem you're having reinstalling Audition 3.01 is because, several year ago, Adobe took the activation server for old versions off line. However, Adobe have made provision for customers like you--you can download a new copy of 3.01 that you can activate with a generic serial number which they provide. If you want to do this, this FAQ gives details and the URLs: Audition 3 and the activation service
I recommend you read through the whole thing because it gives details of some issues you may have an the addresses also get updated toward the end.