What could these repetitive error messages mean?

[Karjala]

I'm getting the following messages in syslog every 5 minutes (I fetchmail mail from cyrus every 5 minutes):

Nov 18 09:19:09 localhost cyrus/master[1606]: process 2669 exited, status 75
Nov 18 09:19:09 localhost cyrus/master[1606]: service pop3s pid 2669 in BUSY state: terminated abnormally
Nov 18 09:19:10 localhost cyrus/master[1606]: process 2670 exited, status 75
Nov 18 09:19:10 localhost cyrus/master[1606]: service pop3s pid 2670 in BUSY state: terminated abnormally
Nov 18 09:19:10 localhost cyrus/master[1606]: process 2671 exited, status 75
Nov 18 09:19:10 localhost cyrus/master[1606]: service pop3s pid 2671 in BUSY state: terminated abnormally
Nov 18 09:24:29 localhost cyrus/master[1606]: process 2684 exited, status 75
Nov 18 09:24:29 localhost cyrus/master[1606]: service pop3s pid 2684 in BUSY state: terminated abnormally
Nov 18 09:24:30 localhost cyrus/master[1606]: process 2685 exited, status 75
Nov 18 09:24:30 localhost cyrus/master[1606]: service pop3s pid 2685 in BUSY state: terminated abnormally
Nov 18 09:24:31 localhost cyrus/master[1606]: process 2686 exited, status 75
Nov 18 09:24:31 localhost cyrus/master[1606]: service pop3s pid 2686 in BUSY state: terminated abnormally
Nov 18 09:25:43 localhost cyrus/master[1606]: process 2683 exited, status 75
Nov 18 09:25:43 localhost cyrus/master[1606]: service pop3s pid 2683 in BUSY state: terminated abnormally
Nov 18 09:25:44 localhost cyrus/master[1606]: process 2704 exited, status 75

Why could this be happening?

Thx.