first of all, thanks a lot for ISPConfig a so great and useful software.
I tryed a fresh install of ISPConfig 220.127.116.11 and 18.104.22.168 with tre different OS (centos 6.4, Debian 6 and Ubuntu 12.04) following, step by step the how-to, but nothing, always the same error updating package list:
APS crawler: String could not be parsed as XML
After many hours and tests I discovered that the problem wasn't the OS but the open_basedir directive written by the installation procedure:
With those settings, the APS php script cannot access to ISPCconfig directory and to solve the problem is sufficient go to System -> Server Config -> Web -> PHP setting, add the path /usr/local/ispconfig and save the settings.
Now, the command "updating package list" should work without problem.