DIVA-GIS

I was wondering if anyone would be able to help me. I am currently conducting a project based on the Lizard Peninsula in Cornwall, UK, where I have collected distribution data for 8 species. I have imported this information onto a map in DIVA GIS 7.1.7 and attempted to run the software to do the reserve selection./ However, the area I covered is around 30kmx30km, and every time I attempt a reserve selection it gives me a block of about 100kmx100km as a selection, which basically covers all of Cornwall! Does anyone know how I can use the reserve selection tool on a smaller scale? Also, I may be being very dense here, but I can only seem to bring up one species when I select the "SPECIES" field in the parameters, very frustrating!

Any help would be very much appreciated. Thanks!