Just tried it... clean interface/wtf ... installed Pitbull and ArkInv from files.wowace.com (just freshly downloaded, with embedded libs). Pitbull works, ArkInv works... Bank opens fine. No errors, no crash. No idea whats wrong with your bank :-(
me neither :( Bag opens fine with Ark. Just tried again with clean Interface/WTF, installing both addons individually then again with Ark 1st, then Pitbull 1st. cleaning folder inbetween and always the same result - no bank. No errors, no nothing! But when I copy the AceEvent-2.0 from pitbull to Ark and change the .toc it works, sort of.
Are you using standalone libs?