this happened to me when upgrading my bold, it was stuck on reconnecting to JVM, then i just got the 507 error everytime i tried to turn on my phone.
when i followed the 101 nuked bold tutorial, same thing would happen --> stuck on "reconnecting to JVM", i did some searching on google, someone said their laptop with memory problems did the same thing to their phone and so they had to recover it using another laptop (with more RAM)
and then i remembered im using VMWARE on my mac to run windows (only gives windows 256mb RAM), so i upped the memory to 800mb and i recovered my phone! phew!