I may be able to help here....at least, I nhope so.
Two parts to this...one for people who have successfully done it before, then re-jailbroke, and were having trouble accessing the second time around.
The other part for people that are trying to access the first time after a jailbreak...sorry, this is for PC only....obviously, if you are using winSCP,lol
First part,............ I also did the same as the OP, re-jailbroke, but couldnt re-access my touch with either winSCP or CuteFTP using the same passwords and procedures I had successfully used before to install the iphone apps. I kept getting a message which essentially stated that "my keys had changed", this was after re-attempting access a few times. The solution was to tell the program to trust the new keys. Apparently, when you re-JB, it screws with the original connection keys that the access program uses to identify/pair/authenticate a connection with your touch...just tell it to trust/use the new keys and you will be fine. You only need to do this once, it should be clear sailing from there....hope that helps. I think this might be the problem, because some of these posters which tried a new program were then succesful...thats because the new program never "bonded" (generated specific sync keys) with your touch before the 2nd JB.
Second Part,........For those attempting to use the program the first time, and havent JB'd before, you are probably not doing one of three things....first, make sure your IP address is correct (which you get in settings->wifi->properties->IP address), some routers change them from use to use, so what was correct before may not be this time (I am assuming youve read enough to know the default username and password are "root" and "alpine", respectively...both are case sensitive I assume...)
Second, make sure your Wi-fi is on, this works over your wifi network. Third, you should have your touch plugged into the computer (although this might not be necessary from what Ive heard..) Just make sure your "ipod services" and "ituneshelper" are off via your task manager.
Hope this helps, although I am by no means an authority on this subject...this stuff just worked for me, LOL.
...seems that most of the really knowledgable people on this board feel these types of questions are beneath them...I got very little help when I asked the same question....although in fairness, one or two did try.
Good luck!