NSM3.1 for AD, installed on a Windows 2008 R2 server.

I am testing migration from eDir to AD.

Last week, the MigrationProxy account was working well.
Suddenly, since Friday I have message :

"Migration proxy account provisioning failed :
(281) eDirectory NWDSCCODE: ERR_SYSTEM_ERROR [-319]"

I have delete the MigrationProxy account, thinking it will be recreated.
No chance!
What can I do now?