Are you receiving error mentioned in the field?
Do not worry, this error is most probably caused by enabled xCache on your server. The solution is disabling the xCache on your server or disabling the xCache just for the directory with Post Affiliate Pro / Network installation.
You can see this error using the debugger in Chrome or Firefox firebug debugger by using key F12 and navigating into Network and reloading the content of the page in the file installer-3.cache.php in the Response as you can see at the screenshot:
In case of additional problems, feel free to contact us at firstname.lastname@example.org