That client side issue can prolly be fixed by increasing the getwork timeout in the miner sw.
Also, if you take a look at place_json_call() in common.inc.php, you can see it uses inefficient file_get_contents call. Use curl instead.
(benchmark:
http://stackoverflow.com/questions/555523/file-get-contents-vs-curl-what-has-better-performance )
That might give you some space.
If its a source pool problem, in that case, you can tune timeout for your outgoing connections in the place_json_call() as well.
I know I bumped mine up from the default.