I too was experiencing similar problems when using PinballWrapper. I would get the splash screen and occasionally the led display.
The only tables that appeared to load okay were those that didn't use vpinmame (ie: no rom files were loaded).
After much trial and error, I ended up using vp-launch from
http://www.oscarcontrols.com/lazarus/# The main difference between vp-launch2 and vp-launch4 is that vp-launch4 displays a splash screen while loading the tables whereas vp-launch2 displays a black screen (my apologies to the author here as there is undoubtedly a lot more difference behind the scenes than just this).
I now appear to have everything working fine.
I am currently using Visual Pinball 6.1 (if using WinXP SP2 make sure you have the fixed exe), VPMame 1.51 and vp-launch4. Also make sure you have the latest scripts in your tables directory.
My config file looks something like this (this isn't my exact ini file, but should be pretty close from memory)
### vpinball.ini (mamewah v1.61) ###
emulator_title