Error 500 when playing

[zicmama]

Each time I want to play anything on my computer (ubuntu 10.10), I get an error and nothing is played...

Subsonic encountered an internal error. You can report this error in the Subsonic Forum. Please include the information below.
Exception java.lang.NullPointerException
Message null
Java version Sun Microsystems Inc. 1.6.0_18
Operating system Linux 2.6.25.4dedibox-r9-smp-x32
Server jetty-6.1.x
Memory Used 65 of 133 MB
Stack trace java.lang.NullPointerException

But the same works on other computer. I am really confused by this error.
Does it happens to anybody else?

[zicmama]

As many version of subsonic where updated on my server, the problem came from old bad cookie.
After removing all related cookies, the player works!