Safetyminder causing PC to freeze up

So I started trying out this product this week and I've run into an interesting problem.  I've installed it on the desktop in the house and it works like a charm.  However, installing it on my son's mom's computer has caused it to freeze up, regardless of whether the PC is logged into a parent account or a child account.  It'll boot up fine, then you log in and the system starts loading the normal startup software, then it freezes and won't respond - you have to do a hard reboot (*AcK!*).  I did locate some information that said that her version of Zonealarm was incompatible with the software, so I uninstalled that so that we could check before we upgrade her anti-virus - however, the computer continued to freeze up.  The only way to get it to stop unfreezing is by uninstalling it. 

 

She's running a Dell laptop with Windows XP SP3, Intel Core 2 Duo processor at 1.66 GHz with 1 gig of RAM. 

 

Any suggestions for why this might be happening?