Scott,
This sounds like a unique problem, I have not come across this one before.
However, I will dig through our archive and see if any of my colleagues had this problem previously.
Does this happen only in T_Blur?
Meanwhile, I would suggest that a fresh reinstall of the latest version of the plug-ins, in case the files have become corrupted.
You can download Tinderbox 1 here:
https://www.thefoundry.co.uk/pkg_downloads.aspx?ui=BEEF823D-BCFE-4E91-8CC9-0FBFFFB45D0A
You will need to re-serialize the plug-ins with the original CD though.
Please contact me if you have any questions support[at]thefoundry[dot]co[dot]uk.
Regards,
Rob
Foundry Support