Zach - I believe I found the root of the install problem I was having. The VBulletin plugins are turned off after a fresh install of VB is done. I believe vbGallery needs the plugin system to be enabled ? Correct me if I'm wrong.
I did a fresh VB install, enabled the plugin manager, then did a fresh vbGallery install (except for the init.php - did that afterwards) and it seems to be ok - image paths were wrong, but think the installer corrected those.
If the VB plugin system needs to be enable for the vbGallery install (I'm now pretty sure it needs to be), I suggest putting in a step to enable the plugin system before the install proceeds. vbAdvanced installer does have this install step to make sure plugins are enabled, so shouldn't be to hard to replicate that !!