dj - you might want to read up on Kaluza-Klein theory if you're interested in pan dimensional physics... also pretty much anything written by Michio Kaku (his website is here http://www.mkaku.org/) would be of interest

However just to comment

1) dimensions 1-3 are what make up what we commonly refer to as the physical world, the 4th dimension is time. In reality we may also have very rudimentary senses that extend to the 5 and 6th dimensions (possibly higher but who knows). Pancake theory has evolved somewhat more than what you're talking about. You would not be able to use a black hole/wormhole/whitehole to jump intot he next dimension... gravitatioonal forces would annihilate you long before you ever reached the singularity barrier - which would also be terminal. A white hole could be seen because it is emitting radiation (either in visible or invisible EM spectra) - it would not need to reflect light radiation - indeed it could not relect light as it has no true surface to reflect anything off.

2) the 4th dimension is time - yes we are already linked to it. you're now talking about the many worlds theory which has slightly different consequences from the pancake theory. whether you can actually change time is however a different matter - it is speculated that even if it is possible to travel in time it is only possible to change the future not the past.

Einstein - whilst far brainer than me.... and much kudos goes to him... lost it to an extent - like many scientists he fell into the trap of thinking his theories were exclusively correct, he wasn't willing to modify his theories in the face of overwhelming evidence (IMO thats one thing which Hawking does have my respect for, he is willing to stand up and say 'I'm wrong'). Being convinced you're right and everyone else is wrong is not always a good thing. Having said that one bad thing about Hawkings latest comments is

“There is no baby universe branching off (inside a black hole), as I once thought. The information remains firmly in our universe,” Hawking said in a speech to about 800 physicists and other scientists from 50 countries. “I’m sorry to disappoint science fiction fans, but if information is preserved, there is no possibility of using black holes to travel to other universes.
http://www.msnbc.msn.com/id/5473323/

which is something I personally find quite depressing (and I also think its untrue but until I find a copy of Hawkings damn transcript I'm going to have to sweat this one out)

Your logic on this score is exceptionally woolly. Where did you get the idea that a black hole has to go backwards in time for example?? In any case it doesn't necessarily create a paradox.... a 'circle' can have input coming from a different direction which you have no concept of (hint: in a 1D perspective, a sphere - a 3D object- is viewed as a circle. If you're an omnipotent being you aren't restricted to one dimension... what might appear as one thing to you - living in 1D land- may actually only be a part of a whole 3D entity.)

3) quite possibly this is the case... in which case everything is totally pointless

On that note i'm going to meditate before going to sleep - I have to be up in 5 hours