I had few problems and here is the advice we received from dnnsoft.com
If you get any errors while uploading pa-modules or importing and exporting products, orders etc., this may be caused by a slow internet connection or your provider has limited the maximum amount of time for a script to execute. To fix this, you can use also the ftp method to install the modules: Ftp the 3 pa-module files to /Install/Module folder and then give a command at the /Install/Install.aspx?mode=InstallResources or Host -> Module Definitions -> Available Modules -> Select Modules -> Install Selected Modules, or perform the steps below
Change this line in your web.config:
< forms name=".DOTNETNUKE" protection="All" cookieless="UseCookies" timeout="60" />
to
< forms name=".DOTNETNUKE" protection="All" cookieless="UseCookies" timeout="600000" />
and change httpRuntime code
< httpRuntime useFullyQualifiedRedirectUrl="true" maxRequestLength="2097151" requestLengthDiskThreshold="50000" executionTimeout="9000" />