A search produced a couple of suggestions:
"Try deleting the iPod Photo Cache folder (located in your Pictures folder) and then, sync again.
Don't worry, iTunes will re-generate it the next time you sync your iPodhttp://www.hackint0sh.org/tools-128/problem-cant-sync-how-resolve-error-54-a-38375.htm
See the first post where it says "this solved the problem" in the Apple Forums at https://discussions.apple.com/thread/1912814?start=0&tstart=0
Open Disk Utility (in your Utilities Folder, which is most likely in your Applications Folder)
Once it opens, in the sidebar, most likely as the first item, you will see your hard drive with a somewhat unusual name that indicates its size and manufacturer ID. Directly below that and slightly indented is your HD volume, which might be named "Macintosh HD" (unless you renamed it). Click on it to select it.
The "Repair Disk Permissions" button should now be available below the large empty window. You may wish to check "Show Details" above that window so you can see what gets repaired, but click the "Repair Disk Permissions" button.
If none of the above suggestions solve your problem, report back with specifics.
One last thought: are you NOT logged in as "guest"? Restart and see if things change.