rsh problem

Hello,

my laptop with qnx is unable to rsh another qnx computer. I could ping it,
but when I rsh, I got the following message:

mwt7# ping mwt5
PING mwt5 (192.168.1.105): 56 data bytes
64 bytes from 192.168.1.105: icmp_seq=0 ttl=255 time=2.999 ms
64 bytes from 192.168.1.105: icmp_seq=1 ttl=255 time=3.000 ms
64 bytes from 192.168.1.105: icmp_seq=2 ttl=255 time=3.000 ms
64 bytes from 192.168.1.105: icmp_seq=3 ttl=255 time=3.000 ms
64 bytes from 192.168.1.105: icmp_seq=4 ttl=255 time=3.000 ms

----mwt5 PING Statistics----
5 packets transmitted, 5 packets received, 0.0% packet loss
round-trip min/avg/max/stddev = 2.999/3.000/3.000/0.000 ms
mwt7# rsh mwt5
rlogin: read: No such process.
rlogin: connection closed.
mwt7#

It occasionally works if I reboot the computer. Could somebody kindly tell
me if there is some setting I need to change? Thanks.
Both computers (mwt7 and mwt5) use QNX 6.2.1.

Johnson