Hello Shoggoth,
I'm really sorry, I couldn't reproduce your "No Class Expression" issue. I tried both opening the compo you sent with the latest beta Smode version and with the public 8.1 version and in both cases, the compo opens perfectly fine without any error message.
So, I really have no idea of what's going on.
Two things you can try:
1) Fully reset your install of Smode by deleting all the content of the following directory:
C:\Users\%yourusername%\AppData\Roaming\Smode Studio
2) Try with the latest beta version (I send you the link by PM)
Best,
Francis.