Looks like your PHP config (php.ini) doesn't allow more than 1GB of memory, thats really huge for PHP scripting.
make sure u don't procedure an endless loop. When perform an endless loop with huge files or large database queries, it can happen that the memory gets full before the script stopped working by max_execution_time error.
If your provider allows, you can extend the memory usage by give it ini_set("memory_limit","2G") or more if needed (not recommended).
if u really want to debug this, use php "self-debuggers" in this case, put
echo "<pre>".print_r(debug_backtrace(),true)."</pre>";
exit;
before the error occurs, this display the full stack tree with args, methods, ...
You also can store the output of debug_backtrace() in a var and handle it by yourself.