I have the same problem. I've posted it in the KMyMoney forum but haven't received an answer yet. Therefore, I have written a wrapper in bash to circumvent the problem:
Code:
#!/bin/bash
FILE='/home/SHARED/finances/compta.kmy'
chgrp accounting $FILE
chmod g+w $FILE
/opt/kde/bin/kmymoney $FILE
chgrp accounting $FILE
chmod g+w $FILE
Try if this works for you as well.