To be able to refer to the bookmark directly, you'd need to ensure it doesn't include the end-of-cell marker. See the Testing and Returning Cell Contents in Tables topic for an explanation.

As for the syntax, it should be:
{IF{REF Ship}= "Free" "NA" {=IF(C7<200,4.95,{=IF(C7<500,7.95,10.95)})}}
Note the required spaces.

__________________
Cheers,
Paul Edstein
[Fmr MS MVP - Word]