Wirelessly posted (Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.0) BlackBerry8703e/4.1.0 Profile/MIDP-2.0 Configuration/CLDC-1.1 VendorID/104)

I personally haven't been able to use myspace with the native BB broswer under several configurations, however I have been able to use mypsace after downloading the opera mini browser. Try that and hopefully it shall work to suit your needs!