can't find the right hook

[JPnyc]

hi folks, I have a plug-in I wrote some time ago which, when hooked on register add member process, works fine. However registration is going to be taken away from me, the database is going to be written to directly, bypassing the vbulletin installation, entirely. I need to hook this someplace else prior to the posting process. I tried show thread start and complete, user online, all of which prevented the page from loading. I know the plug-in works so I assumed that it had to interfere with other functions that follow

What function or hook is connected to the loading of the page, particularly any page where posts could be entered? Thanks in advance.