I have the same Problem. I exported a part of one Zotero library and the import into a new zotero library failed. I have the newest firefox and zotero version.
if someone could help I would be very grateful

Hi Simon, sorry for unclear infos. So I'm using Zotero 2.0 and firefox 3.6.12. I try to made a report ID but i was not that succesful but i made a Debug ID (D946180975) i hope it is helpfull for you to.
Thanks

cumuluss, your original issues were related to quotations in the URL field, which the RDF parsing library wasn't escaping properly. This is now fixed in Zotero SVN.

The problems you seem to be experiencing now are related to path length. Your RDF is exported with files, and some of your snapshots contain files with very long names (187 characters). While this wouldn't be a problem on Mac OS X or Linux, Windows does not support paths of more than 255 characters. There is an open bug to handle this situation better, but for now, you have a few options. You could update the Data Directory Location within Zotero and move your Zotero data directory to a lower level of your drive, which should allow you to import your files without error (provided the new directory has a short enough path). You could also first copy the original directory to your Zotero data directory, then move it out and import it. When you perform the copy, Windows will refuse to copy some items because the path would be too long, but based on the files you sent me, it looks like these files with long names are images associated with HTML snapshots that should not affect your ability to view the text.

Finally, if your goal is to transfer your database from one computer or drive to another, copying the Zotero database directly would be preferable to exporting and importing. (However, unless you move your Zotero data directory as above, Windows will still balk at copying some of the snapshot-related files when you restore your database. It's your choice whether you're willing to live without them.)

For merging two libraries, your best bet is probably import/export after resolving the path length issue using one of the solutions above, unless your attached files are <100 MB or you have paid for a Zotero File Storage account of sufficient capacity, in which case you could set up sync on both libraries. The only benefit to the latter approach would be that word processor documents created with either library could still be updated. (With export/import, only documents created with the library you are importing into can be updated.)