Sorry I've been posting soooooo much lately - if I'm eating up all your time, feel free to wait on this one

So I'm trying to run multiple drivers from the same machine. Here's what happens - the first one launches just fine, but when I launch subsequent drivers from the same machine, they always die within seconds of starting up. No warnings are printed either. Here's what happens:
//driver 1 output:
log4j: Using URL [file:G:/GMPSys/config/log4j-driver.properties] for automatic log4j configuration.
log4j: Reading configuration from URL file:G:/GMPSys/config/log4j-driver.properties
log4j: Parsing for [root] with value=[INFO, JPPF].
log4j: Level token is [INFO].
log4j: Category root set to INFO
log4j: Parsing appender named "JPPF".
log4j: Parsing layout options for "JPPF".
log4j: Setting property [conversionPattern] to [%d [%-5p][%c.%M(%L)]: %m
].
log4j: End of parsing for "JPPF".
log4j: Setting property [file] to [logs/jppf-driver.log].
log4j: Setting property [append] to [false].
log4j: setFile called: logs/jppf-driver.log, false
log4j: setFile ended
log4j: Parsed "JPPF" options.
log4j: Finished configuring.
Class Server initialized - listening on port 11111
Client Server initialized - listening on port 11112
Tasks Server initialized - listening on port 11113
JPPF Driver initialization complete
//Driver 2 Output:
Driver "AwesomeDriver2" terminated abnormally, see output below:
log4j: Using URL [file:G:/GMPSys/config/log4j-driver.properties] for automatic log4j configuration.
log4j: Reading configuration from URL file:G:/GMPSys/config/log4j-driver.properties
log4j: Parsing for [root] with value=[INFO, JPPF].
log4j: Level token is [INFO].
log4j: Category root set to INFO
log4j: Parsing appender named "JPPF".
log4j: Parsing layout options for "JPPF".
log4j: Setting property [conversionPattern] to [%d [%-5p][%c.%M(%L)]: %m
].
log4j: End of parsing for "JPPF".
log4j: Setting property [file] to [logs/jppf-driver.log].
log4j: Setting property [append] to [false].
log4j: setFile called: logs/jppf-driver.log, false
log4j: setFile ended
log4j: Parsed "JPPF" options.
log4j: Finished configuring.
Class Server initialized - listening on port 11115
Client Server initialized - listening on port 11114
Tasks Server initialized - listening on port 11116
At this point, Driver 2's process terminates - no warning, no exceptions, nothing. Both drivers are using identical command-line options, except they are using different config files with different port numbers specified. Other than that, they are running using identical settings.
Any ideas?