DCB4W

Aerie's variable is set at 3 (so are Viconia, Neera, and Jaheira, FWIW), and the problem repeats with Isra even with Aerie out of the party.  I went back to a much older save and bumped the Isra romance up to 2 and the love talk to 35, and set the PC's other romances to 3. Aerie wasn't in the party at that point, so Isra is the only conflict. (Unfortunately, it's still unplayable with one character moving about 3' per mouse click.)
 

Experimentation reveals that it's the ISRAROMANCEACTIVE variable going to 2 that triggers the glitch.

Hi, I'm the same person as David above. I made a new account. Thanks for getting back to me so quickly.

Both of those variables are set at 3 already.

I've tried booting Aerie and Isra out of the party and having them rejoin, and changing their scripts with no luck.