If you run a process that opens and closes connections very fast, the Oracle 10g XE listener fails with the following error:
Connection refused(DESCRIPTION=(TMP=)(VSNNUM=169869568)(ERR=12519)(ERROR_STACK=(ERROR=(CODE=12519)(EMFI=4))))
To fix this problem, simple change the number of processes in the SPFILE to a large number (see example below).
ALTER SYSTEM SET PROCESSES=250 SCOPE=SPFILE
The alter command requires a DB restart.
This seems to have fixed my problem... or delays the error from occuring.