PHP 5.3.9 introduced a new configuration variable max_input_vars http://www.php.net/manual/en/info.configuration.php#ini.max-input-vars which causes trouble when submitting forms with lot's of data (e.g. thousands of hosts). Additionally, there's an extension called Suhosin, that also limits this parameter. This should be considered because it comes be default with the debian lampp package.
So, basically, we need to add checks for the following parameters in our setup:
It would also be great to improve the overall logic of the setup, so it could check if:
1. some of the values could be set at runtime and not ask the user to set them themselves;
2. check, what parameters are relevant to the current configuration, i.e. ignore "max_input_vars" if PHP is older then 5.3.9, or ignore suhosin parameters, if it's not installed.