Repairing is only possible if it is a true virus. With other malware (worms, trojans, spyware, adware and such) the only remedy is to remove the files.

You may want to take a look HERE for definitions.

As you can see in the virus library (start avast > menu > virus library) Avast can not repair the infected file(s).

I suggest you send it to the virus chest.
When it is there make sure it is indeed malware. (run a online scanner like JOTTI to scan the chest folder.
If it is indeed malware, and I think it is, delete it from the virus chest.

That should solve the problem.

In addition you may want to read THIS page for aditional information on how to clean/secure a system.

Let us know if the problem is solved or not. And remember:
There is no need to rush. Take your time. Better slow and safe than fast and still in trouble :wink: