While looking through the documentation section (http://getpopfile.org/docs/), I found that the "Forum Search" link (http://popfile.manni-heumann.de/forums/) did not resolve. I then tested it using Down For Everyone Or Just Me, and confirmed using command-line tools (whois, dig). (Test results provided below.)

If there is a method of contacting the individual who was maintaining that link, it may be worthwhile to contact them to determine if it is no longer active, or when/if it can be expected to be restored.

Update: Removed WHOIS output.