No - there is definitely something wrong here.  I'm not being paid for any blocks anymore

17774   2013-04-30 20:25:35   2:03:23   14233698   132   0.00000000
17775   2013-04-30 23:59:52   3:34:17   24772020   145   0.00000000
17776   2013-05-01 02:25:35   2:25:43   16453036    13   0.00000000

I have moved over to another pool, and I'm not having problems there with zero returns per block, even if my share counts are low.

41  DGM  0 PPS   0.00108057
136 DGM 0 PPS   0.00110942
464 DGM 0 PPS   0.00132832
6    DGM 0 PPS   0.00068256