Sinatra hangs seemingly without a reason

I have a strange problem with sinatra...

In my app the login form is checking with AJAX live whether a nickname is already 开发者_运维百科taken or free... This works fine 90% of the time... But sometimes, randomly, I get no response from the given route anymore... in the console log all new requests to this route are missing as if I haven't sent anything... but other routes seem to be fine...

And when that occurs, if I shutdown sinatra, it begins to obviously hang. it says:

[2010-08-29 22:41:12] INFO  going to shutdown ...

but the process does not terminate anymore until I close the console window.

I checked my client side code - it works fine... I also checked the code in the route itself... (only about 7 lines) - its fine too (the only method, the one which accesses the database, works flawlessly in all other circumstances)

So the only explaination I came up with that it must be a Sinatra bug...

Has someone experienced something similar? If not... do you agree? Should I file a bug report? And what shall I write into that report? The bug is much too... random...

UPDATE:
    enable :lock unfortunately doesn'nt help...
    I tried to use hijack... it doesn't seem to work on the process
    (I used the pid given by WEBrick)

Well, must have been activerecords fault, after all...

I switched to DataMapper and the bug was gone..