Download a copy of knoppix, burn the iso (if you have nero, roxio or whatever burning app, right click the iso and in the properties tab select open with either nero, roxio, or whatever. Now simply double clicking an iso image will open your burn application and burn the iso properly). Boot into the cd/dvd (press whatever key your pc requires to enter setup (your bios) and set cd as the first boot device). Now with the knoppix linux desktop loaded, plug in your ipod and it will open or display an icon on the desktop you can open. You should be able to load/delete what you want to and from your ipod. Sorry forgot you will need to make the ipod writable first by right clicking on it , selecting actions and then "make read writable" then ok. point is if this works for you and you can copy to and from your ipod it will rule out there being anything wrong with your ipod and point at windows as being the culprit.
You might be able to copy your stuff off the ipod and reseting it in itunes and redoing rockbox after you recopy everything. Another option might be in windows again go to my computer, right click on your ipod icon, select properties, tools and then error checking, check the boxes for fixing errors etc then ok. Might be something is currupted and error checking should fix it. 8-)