Keep Getting Invalid Serial Number when installing Adobe Acrobat Pro 9 after downloading from http://helpx.adobe.com/uk/acrobat/kb/acrobat-8-9-product-downloads.html

When installing Acrobat 9 Pro after downloading from: Download Acrobat products | 9, 8 I keep getting invalid serial number, even though this is the correct serial number and is shown in My Adobe.

Is there another download available to try?