Executing 16-bit app causes instant reboot

[hake]

I had been using The New Shorter Oxford English Dictionary (1997 version) with Windows 98SE, Windows 2000 and Windows XP since 1999.  Until Avast 5.1.684, it worked.  The first time I used it after updating to 5.1.684 the system immediately rebooted.  It happened on two other systems.  This is not a problem for me as I had a later Oxford Dictionary available to install and it works like a charm.

I raise this issue in case 16-bit apps are a problem with Avast 5.1.684.

[pk]

I tried with igor some win 16-bit apps, but they work ok here.
Do you have some minidumps in \Windows\minidump folder? Thanks.