I am using F-secure (Anti-Virus for Workstations 7.00 build 220) and according to it Cannon Fodder is clean, it might be a false positive. However, leave it untill you are completely sure. You could try some different AV scanners to find out if it might be a false alarm, for example you could test it on kaspersky's online scanner:
http://www.kaspersky.com/scanforvirus
This is actually mentioned in the
cannon fodder thread, so you might want ot read that too, not really any clear answers though, but it seems it's only Avast! that complains of it.
- Arand