Am trying to upgrade to mavericks from Lion 10.7 but whenever i press upgrade, i told that The server gave an error during download: 403 Forbidden.

Am trying to upgrade to mavericks from Lion 10.7 but whenever i press upgrade, am told that ``The server gave an error during download: 403 Forbidden``.

Below are my hardware specs. Does anyone have an answer to this?

Hardware Overview:

Model Name: Mac Pro

Model Identifier: MacPro4,1

Processor Name: Quad-Core Intel Xeon

Processor Speed: 2.93 GHz

Number of Processors: 2

Total Number of Cores: 8

L2 Cache (per Core): 256 KB

L3 Cache (per Processor): 8 MB

Memory: 9 GB

Processor Interconnect Speed: 6.4 GT/s