Hi Rgkarsr, welcome to the forums.
This is the Panda ActiveScan - Online scanners virus signature file, because it is not encrypted the virus signatures can be seen by other AVs and they are looking for the same signatures when checking for infection.
avast sees the signature and reports the virus, you can delete the pav.sig file I you chose to use the PAV online scanner again (although I would tend to use one of the other online scanners), it would download the latest sig file.
OnLine Virus Scanners
TrendMicro's
HousecallBit Defender
On-line ScannerF-Secure
On-line Scanner ActiveX required
These are just a few of the many on-line scanners out there, check out RejZor's Website - Security Ops for more On-line Virus Scanners
Security.Ops.tkHTH David