Blackberry and vodafone xxl Internet Flat - streaming dont work!

I use a Blackberry Bold 9000 and a vodafone xxl Internet Flat.
When i connecting with the integrated browser to m.yourmuze.fm, logging in and selecting a station,
my BB mediaplayer opens and after a moment of loading appears an
ERROR-Message:
"Inhalt nicht verfügbar. Der Server ist blockiert oder reagiert nicht."
this appears in other 3rd party bb browsers like BOLT BROWSER or OPERA MINI, too.
On any other nonblackberry phone with data flat it works fine.
Can you tell me , whats the problem?

Big THX for help!

here just an Add: when i try to connect in the same way to yourmuze station but via LAN, it works fine !
it seems so, that the BB Server is blocking any port or sth like this...