This was slowing me down for awhile...
Under Eclipse Helios, if I changed something in the config .ini file, Eclipse would not reliably rebuild and reinstall the .apk. A lot of the time it would print "already deployed" and run the version installed on the device before the changes.
I enabled the option Window | Preferences | General | Workspace | Refresh automatically. Now, when I save a change to the .ini file,
Eclipse detects this and builds and installs the new .apk on the device.
Just posting in case this helps someone else!