AccelePort 16em PCI Xem

I have installed a new Fujitsu Siemens Econel E30 at one of my customers site with a AccelePort Xem 16em PCI card and a 16em concentrator.I loaded the latest Red Hat Linux 7.2 driver for this card and I have re-installed the server for a second time having reloaded Red Hat Linux 7.2 and the driver,but what happens is that the server starts to slow down and when typing in commands the server does not respond.Almost as if the server hangs up.When typing in the same command two minutes later it responds again.What could be causing the problem?

Does the slow down only occur on the Digi ports or is it seen on the console/built in serial ports also?

What driver version?

What kernel version (up/smp)?