Problem with cvsimport

Hello

When I try to import a project into git with the cvsimport tool, it works fine most of the time. I obtain a clean repository without all thoses CVS directories.

But sometimes during the import the cvs server hang and i need to do Ctrl+C the restart the command. cvsimport skip the already downloaded patchset but at the end I obtain this message

---
Generating pack...
Done counting 1534 objects.
Deltifying 1534 objects...
 100% (1534/1534) done
Writing 1534 objects...
 100% (1534/1534) done
Total 1534 (delta 1160), reused 0 (delta 0)
Pack pack-8fb4f1c25c831ba29c7bd53989cb1b445b60bc07 created.
Removing unused objects 100%...
Done.
DONE.
fatal: Needed a single revision
Can merge only exactly one commit into empty head
Could not merge origin into the current branch.
---

So to resume:
* In one shoot no problem at the end cvsimport checkout the
right head.
* multiple shoot impossible to merge origin into the current branch.

How this problem can be solved ?

Thanks

Frederic