Ok.... I too have an 8110 Pearl, and was trying to do the software upgrade form T Mobile (my device had started rebooting itself after what I suspect was an OTA upgrade they pushed out so had to see if could upgrade the software) I had the app loader 200 error during the upgrade and have just followed the really informative instructions re JL tool (many thanks for that). Managed to get the device to the 507 icon / error. Tried the app loader via the dtm and kept getting fatal error after it had run the wiping handheld step. Thought I'd try the cmd steps the JL tool instructions link to, to see if that would help in case it hadn't managed to use the JL tool (java prob or something) (Again, great instructions - many thanks).
So...it did the:
- load JVM and sys software
- wait for device reinitialisation (red light... great... progress....)
then got the egg timer but was a bit concerned as it was the small version rather than the one the OS has....)
- started the Read App config bit and then bb showed 507 error and icon again, and I got another version of the 'a fatal error has occurred' message I got via the DTM. Unspecified error encountered - J:0000005
Can anyone help an amateur sort this out please.....