I have not seen this problem earlier. Are you using the latest version of the SAP BC. Try increasing the JVM size. Make sure the min and maxmem is more than the default setting that it comes with.
Is there a particular action you are taking when the error occurs? I know you mentioned it is on a “Save”, but is there some action in the Developer that you taking that seems to trigger the problem?
Also, what versions are you running and what patches have you installed?