Error 500 after updated Server 2.5 in some PCS

Hi,
I Updated  the server version to 2.5 and after that all the computers started showing in the log:

  ERROR *** AGENT => Failed to send Inventory <HTTP Status Code # 500>

Some computers are not inventaried but other are. I tested my computer with windows agent 2.4. and older version with same result.
In ocsreports nothing is displayed in the software inventory. The list of software is empty in the computers.

But testing reinstall agent 2.4  with Nosoftware=1  to not inventoried software, I have checked that it does not give the error 500 and all the computers will be inventoried.

What's the problem? Any problem with de DB?

Thanks.