the parting surface must be larger than the boundary of the sketch

Hello,

I've been trying to make a mold for an old part as practice. I'm a student and very much a beginner at solid works and especially mold making. I got to tooling split, but I'm having the error "the parting surface must be larger than the boundary of the sketch."  I have read other forum posts on the subject and have been watching some instructional videos, but I'm not making any further progress. I attached the file I've been struggling with. Any help would be very much appreciated.

Thanks

SolidworksPlastics And Mold Design