Unable to set server hostname

How long have you waited? It can take a few days for that to update. The new information is out there now, so if you're in a substantial hurry, try rebooting all of the IRC servers and the DNS servers they rely on. That should clear any caches with the old data.

rtucker@witte:~$ dig +short suprtech.com
96.126.123.68

rtucker@witte:~$ dig +short -x 96.126.123.68
suprtech.com.

I set everything yesterday, rebooted everything this morning

The message that appeared when you set your reverse DNS, "Please allow up to 24 hours for changes to take effect," was correct. Nameservers are permitted to cache these records for 86,400 seconds, and they will do so. "dig -x 96.126.123.68" from the IRC server in question will show how many seconds are remaining:

;; ANSWER SECTION:
68.123.126.96.in-addr.arpa. 86101 IN    PTR suprtech.com.

In this case, it could be 86,101 seconds before my nameserver will forget that answer. Rebooting anything other than the nameserver(s) used by the IRC server(s) (and perhaps the IRC servers themselves) will not make that go any faster.