If you are manually typing the address, because of its length, I will bet you a bowl of grits you have entered it incorrectly.
Give the difficult method a shot and click on the ota link via your BB browser, and it will automatically enter the correct address for you in a nano-second, then continue with the download. The link works, I just confirmed it before typing this.
Good luck.
Posted from my CrackBerry at wapforums.crackberry.com