Problem with Xcode

Hi to everyone,

Since I work on MacOs 10.6.8, I had to download and install the Xcode version 3.2.6 (compatible) from Apple Developer.

Nevertheless, when the installing process is almost over, a little screen shows up and gives me this: "There is an unknown error and Xcode couldn't be installed. Contact the software technical support for some information". So, I don't know what to do! I'm not a professional developer and I don't really know so much about computers; so I wanted you to give me a hand, if you don't mind.

Thank you very much.