You get rounds where you get nothing.. Yeah well look at this!
Time/Link Found in Total shares Reward
04.06.2011 12:12:13 0h 00m 1379 None
04.06.2011 12:12:05 0h 33m 886855 None
04.06.2011 11:38:23 0h 00m 12618 None
04.06.2011 11:37:52 0h 12m 321595 None
04.06.2011 11:25:30 0h 26m 684876 None
04.06.2011 10:59:27 0h 14m 372365 None
04.06.2011 10:45:23 0h 04m 129117 None
04.06.2011 10:40:25 0h 02m 63443 None
04.06.2011 10:37:57 0h 01m 31884 None
04.06.2011 10:36:40 0h 14m 372853 None
04.06.2011 10:22:17 0h 44m 1176528 None
04.06.2011 09:37:42 0h 02m 55404 None
04.06.2011 09:35:33 0h 11m 299528 None
04.06.2011 09:24:13 0h 23m 623853 None
Something is very wrong. You are either on proportional, or you are mining at an inexplicably slow rate. 1Mh/s is roughly equal to 1 share an hour, so to miss submitting a share during a 44 minute block, you would have to be mining at less than 730Kh/s.
I would have a good look at your client to see if it is properly optimized, or even working for that matter. More info about your setup would be useful too, as I would be glad to help diagnose this peculiar phenomenon.