Oracle Timeout. ORA-02396: exceeded maximum idle time

I got this error while performing an ado.net call to an oracle
procedure that returns a dataset.

Exception of type 'System.Web.HttpUnhandledException' was
thrown.ORA-02396: exceeded maximum idle time, please connect again
System.WebSystem.Exception[]

The process maybe takes 2 to 3 seconds to come back to the webpage.

my vb.net method has cmd.timeout=0

Is my problem there? and is that in minutes or seconds.

My connection string has no timeout setting. Is there a default?

Thanks for any help or information.

re: Oracle Timeout. ORA-02396: exceeded maximum idle time

Forgot to mention, I only sometimes (actually rarely) get the error.
Most of the time everythign works fine. So I think i just need to set
my timeout.