WARNING! Your cache is running out of filedescriptors

And then a number of:
comm_open: socket failure: (55) No buffer space available
records.

Out of mbuf clusters -- adjust NMBCLUSTERS or increase maxusers! shown up on
my FreeBSD 3.4STABLE console.

The usage of fds is low -- about 35 (maximum 220 estimated by me) out of
1064.
Current maxusers=32
Current NMBCLUSTERS=1024

The box is PII, 350Mhz, 256M RAM.

What should I do?

Thanks in advance,
Anar Babayev.