This is a bug that goes back to the original release of The Bard's Tale in 2004. What seems to cause this problem is that the followers or summoned characters in your party try to walk to certain spots for the cutscene to continue, but never reach those spots correctly.
In most cases, you can work around this by summoning different followers, or unsummoning your existing followers entirely. This should allow the cutscene to proceed correctly.
Stuck in cutscene
