Log file shows
[clover-setup] Clover is enabled with initstring 'c:\path\example\mycoverage.db'
However the database is not created at this location.
The initstring is specified in clover-setup and this is called after the compile target.
The <clover-setup> task must be called before sources are instrumented and compiled. If with.clover (which contains the clover-setup task) is called after your target that compiles source, then the initistring will be set after the code as been instrumented, hence will have no affect (as the initstring is set within the code during instrumentation).
Call "with.clover" target which contains the clover-setup before your compile target.