NCELAB complains about 'negative timing check'

Hello everyone there:

I got the following error when using ncelab for the verilog file which
contains timing information like this: $setup(negedge D, posedge CLK,
tsetup_negedge $D$CLK, NOTIFIER); $hold(negedge D, posedge CLK,
tsetup_negedge $D$CLK, NOTIFIER); but I got a bunch of warning like
this:

negative timing check limit not allowed in a 1 limit timing check

Not sure what they mean and how to deal with them. Any input is
appreciated!

-Jerry