To open the file, you must have Adobe Reader (or equivalent) installed on your PC.
If you believe this to be the case, but are still having issues. Please contact me via PM so I can ascertain some further information.
In reference to Mobile Phones, some modern Smart phones (specifically the Microsoft/Windows 7) do allow PDF's to be opened, and apps can be downloaded on other devices to enable this functionality. However on the vast amount of devices, you will receive an error message.
As Gordon has already stated, if you are experiencing issues, the information is also readily available (and often more up-to-date - bear in mind the fixture booklet does not change throughout the month) on the Fixtures page ( http://www.alliancefootballleague.co.uk/Banner_Fixtures.html)