Interface list problem

Hello guys.

We have one stack with some 3com's 5500 EI, but sometime we have problens with IMC, he dont show the interfaces...

Some times list all interfaces, other times show just two interfaces.... I attached one print for us..

Is the newest version of IMC...

Checked SNMP and its ok, i am using SNMP v2c for manage this. Telnet/SSH parameters its ok too.

Othes questions:

Some times i get a problem like this:

"Device "xxxx" denied access."

Someone know what cause it ?

What method he use for get some informations ? Like topology, neighbors, interfaces etc ?

And what he use for SCC works ? I tried use scc but dont works :/

Thanks for all.

Sorry for my bad english :/