Ok I found it.

The "Stored procedure could not be found" error message was effectively due to the fact that the .NET application was not connected to the correct database.

It was...

The .NET application accesses on the database trough a database access library which uses always the same credentials/connection string to connect on the database

Thank you for your response gail.

I will try this option with a log backup every 4 hours and see how big the log are growing. I will come back...

Hi,

Thank you for your advises.

Well for the server hard drives configuration we have currently two arrays :

C: (70gb) containing the logs and OS in raid 1+0

D: (210gb) containing data and...