I've seen this error, a long time ago. I just forgot how to fix it...

When telnetting into localhost on the pop port (with the precompiled
binary of qpopper found at macbsd.co in contrib/unix installed), I get the
following error:

[otaku@otaku.users.netset.com]% telnet localhost pop
Trying 127.0.0.1...
Connected to localhost.
Escape character is '^]'.
+OK QPOP (version 2.2) at otaku.users.netset.com starting.
user otaku
+OK Password required for otaku.
pass mypass
-ERR System error, can't open temporary file, do you own it?
+OK Pop server at otaku.users.netset.com signing off.
Connection closed by foreign host.

Anyone know the answer?

Thanks a lot for any help,

Josh