Panda Antivirus does not encrypt its virus database - the signatures inside are clearly "visible" to other antiviral programs, so they detect this file as infected (but there is actually no virus inside - only the signatures are the same).

Anti-virus scanners use virus definitions to check for viruses. These may be a fragment of the virus code. Although inactive and harmless, these definitions may be recognised by other anti-virus programs as the virus itself. For this reason, most anti-virus and anti-spyware programs encrypt their definitions so that they do not trigger a false alarm when scanned by other security programs. However, some programs do not encrypt their definitions and so will cause false alarms if used while a resident anti-virus program is active.

The most notorious are Trend Micro and Panda. If you receive a virus warning while using these products, it is not because they are trying to infect your computer with malware: they simply have unencrypted definitions and it is essential to disable any resident anti-virus before using them.