Zimbra Desktop Problem

[zuze]

Hi,
After installing Zimbra Desktop Alpha v0.53 for Windows, I cannot open it. When I double click on Zimbra Desktop icon I get the error message : "Windows cannot find http://localhost:7633/mail/home"
If I typed this URL directly into IE or Firefox, the setup wizard would open and allowed me to setup an account. The problem now is when I clicked on Launch (after the test was successful) I got this error:
" HTTP ERROR: 404

/h/search

RequestURI=/zimbra/h/search"
I can access this mailbox directly from the server (click on the account -> View Mail) I can send and receive emails without any problem. Zimbra toaster works fine on my desktop.
My server is running Ubuntu 6.06.1 and ZCS-Network-5.0.0_GA_1869 for Ubuntu 6.
Any idea?
Thanks