Mac OS X

Here's the procedure for manually uninstalling the AnyConnect client from a Mac OS X system:
As root, run the following shell script from the Terminal:
$ sudo /opt/cisco/vpn/bin/vpn_uninstall.sh
You will be prompted for your password. Once you enter it, just follow the steps

If you still having trouble and/or the new Cisco Anyconnect installation complains that you have a version installed, follow these steps:
Enter these commands to clean out the old Cisco VPN kernel extension and reboot the system.

sudo -s
rm -rf /System/Library/StartupItems/CiscoVPN
rm -rf /Library/StartupItems/CiscoVPN
rm -rf /System/Library/Extensions/CiscoVPN.kext
rm -rf /Library/Extensions/CiscoVPN.kext
rm -rf /Library/Receipts/vpnclient-kext.pkg
rm -rf /Library/Receipts/vpnclient-startup.pkg
reboot

If you installed the Cisco VPN for Mac version 4.1.08005 package, enter these commands to delete the misplaced files. The deletion of these files will not affect your system, since applications do not use these misplaced files in their current location.

sudo -s
rm -rf /Cisco\ VPN\ Client.mpkg
rm -rf /com.nexUmoja.Shimo.plist
rm -rf /Profiles
rm -rf /Shimo.app
exit

Enter these commands if you no longer need the old Cisco VPN Client or Shimo.

sudo -s
rm -rf /Library/Application\ Support/Shimo
rm -rf /Library/Frameworks/cisco-vpnclient.framework
rm -rf /Library/Extensions/tun.kext
rm -rf /Library/Extensions/tap.kext
rm -rf /private/opt/cisco-vpnclient
rm -rf /Applications/VPNClient.app
rm -rf /Applications/Shimo.apprm -rf /private/etc/opt/cisco-vpnclient
rm -rf /Library/Receipts/vpnclient-api.pkg
rm -rf /Library/Receipts/vpnclient-bin.pkg
rm -rf /Library/Receipts/vpnclient-gui.pkg
rm -rf /Library/Receipts/vpnclient-profiles.pkg
rm -rf ~/Library/Preferences/com.nexUmoja.Shimo.plist
rm -rf ~/Library/Application\ Support/Shimo
rm -rf ~/Library/Preferences/com.cisco.VPNClient.plist
rm -rf ~/Library/Application\ Support/SyncServices/Local/TFSM/com.
nexumoja.Shimo.Profiles
rm -rf ~/Library/Logs/Shimo*
rm -rf ~/Library/Application\ Support/Shimo
rm -rf ~/Library/Application\ Support/Growl/Tickets/Shimo.growlTicket
exit

Finally this.

sudo pkgutil --forget com.cisco.pkg.anyconnect.vpn


These files are mostly likely meta-data files for OS X's HFS+ file system. See this entire thread on the Apple Stack Exchange for some good starting points if you're interested in the details.
Oversimplifying things, when you create a tar archive on OS X these files are included along with the "real" file. This allows Macintosh specific meta data to survive the trip into a file format that wasn't created specifically for the Mac. If you untar the files on a Mac, the meta-data is preserved. If you untar the files on a non-Mac, the ._ files are generated in case the meta data is needed.
My guess is, at some point someone tared up those files to move them to the production server from their Mac, which brought along the the ._ files for the ride. You can avoid this in the future by running
export COPYFILE_DISABLE=true
from the terminal prior to copying the files. Details on this here.
(It's pretty bizarre that PHP would attempt to include those files instead of the correct files — did you debug this far enough to know why/what connect through it was doing?)

In order for an Apple computer to bind and synchronize the mobile account with the Open Directory account on OS X Server the DHCP settings must receive consistent DNS information for that server. However with A1 the router allows only using the search domain of .home. However, for consistency, the search domain must match the domain name of the Open Directory server.
If your mobile account won't synchronize with the server, and the server's domain is not .home, check that the Search Domain listed in the System Preferences, Network settings is correct. It is .home if you received your DHCP lease from the wireless network router provided by A1. Change this to match the domain name for your server. If your server is named xxx.tuwienrocks.at, then enter the search domain tuwienrocks.at. Additionally, it may be preferable to have manually entered DNS server data referencing the OS X Server itself. This ensures DNS record consistency between the client computer and the server, which is required to bind to the server and synchronize the mobile account
After changing this domain name and DNS server, it is a good idea to create a new location specifying the home network to store these DNS and search domain settings. When you are at that location use that preconfigured location, otherwise use Automatic for your Network Location.

Workaround: Enable the accessibility full keyboard based interaction for handicapped users by pressing Command+F5, the system will switch from a list of user icons to display two text fields. It will beep once and you can then enter the user name, press tab and it will beep twice. Enter the password for the user account. If successful you will then be presented with the normal user account login screen. Press Command+F5 again to turn off the Accessibility features.

Warning: You must know the username and password for at least one user account in order to authenticate and decrypt the disk which will give you access to the standard login window.