I have an example here that works in FB6, but stopped working in 7. (Forgot to log this yesterday) My other XML Edit actions are working, but this more complicated one is failing. I've attached FB6 and FB7 samples.
This is a side effect of defaulting to MSXML 6 in FinalBuilder 7 (FB6 uses MSXML 4).
The good news is the build I posted yesterday already has a new option to deal with this on the XML Document Define action (Allow DTD’s). Unfortunately it looks like it is only available when MSXML 6 is explicitly set, which won’t work if you have Highest Available set. I just checked in a fix for that, will post the build url here when it’s done.