Problem solved...

There were a lot of cmd processes blocked in the server.

So for sql was impossible to gain acces to another session of external command...

A virus was found.

With virus removed...

Yes.

This is driving me crazy.

I don't think this can be a security problem. (I use sa as username running my code).

In any case...

There is a smarter way to know if...

Sure. The code is:

/*Code starts here*/

DECLARE @retValueINT

DECLARE @strSqlVARCHAR(1000)

DECLARE @RemoteUsrVARCHAR(50)

DECLARE @RemotePwdVARCHAR(50)

DECLARE @ServerName VARCHAR(50)

SET @RemoteUsr = 'sa'

SET @RemotePwd = 'RightPasswordHere'

SET @ServerName = 'servername'

SET @strSql = 'osql -U ' + @RemoteUsr + '...