Sounds like SNMP may not be configured correctly on either the redhat box or the ITA machine.
(ps drop the euro part from the links if in the US)
OK, in fact, I found that ITAssistant requires R/W permissions for SNMP.
I'm not able to access your links: all points to a generci support page (I'm in Europe).
If you are getting the general support page, pick your region, then country.
Enter your tag number (or select I don't know my service tag and pick your model computer from the list)
Once you have the cookie - click on the link again - it will take you directly to the information