squeeze?

Can I ask a Sorenson Squeeze (version 3.5.300.11) question here?
We have been using this workflow for years: Avid>QT reference>Squeeze>ReelDVD, successfully. Lately, when I load a QT movie into Squeeze and select the usual DVD large preset, more often than not it crashes. After 2 or 3 reloads, it eventually renders the entire movie. Nothing in the system has changed- no new hardware, software, etc. Just crashes a lot. Possible hint: We also use a Lacie duplicating tower to make 5 copies at a time. It also has been working fine for years. Lately, it, too has been crashing, with a "read error" message on several, but not all DVDs made using the above process. Coincidence?

Mikey

Avid Xpress Pro Mojo 5.6.7
WindowsXP 2002
HP Workstation XW8000
2.80 Ghz
2.0 GB RAM