Probably you need to increase some php parameters at <b>php.ini</b>
Search the forum, for more info on this parameters, in our experience ezp needs the following values to work properly with a Pentium IV machine :
max_execution_time = 60 ; Maximum execution time of each script, in seconds
max_input_time = 60 ; Maximum amount of time each script may spend parsing request data
memory_limit = 128M ; Maximum amount of memory a script may consume (8MB)