need help making a keygen for a vds program

hello all

I have made a few keygens for software that was made in vds but this one got me stuck here is the code that i think hold the answer.. i have tryed many ways but i can't make a vaild key... any tips would be great...

thanks

%%var16 = @dlgtext(edRK1)@dlgtext(edRK2)@dlgtext(edRK3)@dlgtext(edRK4)
%%var6 = @dlgtext(edRegUser)
if @equal(%%var16,@substr(@enc(@strins(%1,@div(@len(%1),2),@enc(%%var6,215)),md5),7,22))
dialog enable,Save
else
dialog disable,Save