There is a known problem with MapObjects 2.0 and date queries that contain a "12" in the month field (MM/DD/YYYY).
Using the SearchExpression method on date values for the month of December, in any year, returns an empty Recordset. This only applies to shapefiles, VPF, CAD, and coverage data types. Date queries on SDE layers do not exhibit the problem.
There is an additional problem querying dates pre-1900.
This problem is fixed with the MapObjects 2.0a. The 2.0a patch can be downloaded from the Downloads link off of the MapObjects Developer Connection web site.