ILLEGAL: P Bc5-Bc9 on turn 1:
There was no P on . The piece on  is a .
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For diagnostic purposes, here is the full movelist:
1. P Bc5-Bc9 
1... p Bc12-Bc8 
2. P Bb5-Bb9 
2... p Bb12-Bb8 
3. GU Bb1-Bb2 
3... p Db12-Db8 
4. P Db5-Db6 
4... p Db8-Db4 
5. Db1-Db2 
5... p Db4-Da4 
6. Dc1-Dc3 
6... p Da4-Ca4 
7. Bd1-Bc2 
7... p Cc12-Cc8 
8. Cd1-Cc2 
8... .ef Da16-Ba8 
9. .EF Ad1-Ac2 
9... .ef Ad16-Cd8 
10. P Cb5-Cb9 
10... .ef Ba8-Bb7 
11. !F Cc2-Ca4 
11... .ef Bb7-Bd5 //xP
12. P Ad5-Bd5 //PxEF
12... resign
In case there is a bug in the code, the settings file can be edited at /play/pbm/play.php?game=Chess+on+Two+Boards&settings=C02B&submit=Edit