In dialparties.agi, $astman is not being initialised properly. This means that when phpagi_asmanager.php calls 'log', it uses error_log() to log entries. This can be very slow on some PCs. (on our server it takes about 0.1 seconds to log one line). Some AGI calls result in over 100 lines being logged, slowing things down considerably.
This manifested here as queues not working if there was more than one static member listed and is probably the same issue as at http://www.freepbx.org/forum/freepbx/users/queues-dialparties-agi-high-cpu-load#comment-21009
The $astman->pagi member needs to be initialised to the address of an AGI object, so that phpagi will use the much quicker 'VERBOSE' Asterisk method.
A quick fix is to add
$astman->pagi = & $AGI;
after
$astman = new AGI_AsteriskManager( );
at the start of dialparties.agi
A better fix may be to use
$astman = $AGI.new_AsteriskManager();
instead, but I'm not sure if the other effects of the new_AsteriskManager function are desirable or not.