Uncle Ian's statement pretty much wraps up the answer to your dilemma, TeraPox. Apollo was originally, and is still ONLY built for 1.0.2 iPhones, and has not been updated for the firmwares that followed. Meaning it has never been optimized nor expected to be completely functional on iPhones with 1.1.1 and above.
Still, there ARE a handful of users who somehow managed to get Apollo to work on the newer firmwares (including Uncle Ian himself

). But sooner or later, you'll begin to find these sort of dysfunctional problems with the app itself, may it be unable to sign in or just crashing back to Springboard, whether or not it works seriously depends on your luck.
Take the sound advice by Ian, use
BeeJive,
Meebo or
eBuddy instead. They're much more user-friendly, and work a lot smoother too. But take note, whether with Apollo, or any other browser-based IM clients, an IM account with too many contacts will not work out well
This post has been edited by Samanoske Akechi: Jan 30 2008, 02:38 PM