perl Makefile.PL CCFLAGS=-IC:/strawberry/Aspell/include LIBS=-LC:/strawberry/Aspell/lib -laspell

You have not managed to pull in the aspell library.
I would replace "CCFLAGS" with "INC" (because "INC" is the norm) and I would place the LIBS value inside double quotes (because of the space between ".../lib" and "-laspell") :

perl Makefile.PL INC=-IC:/strawberry/Aspell/include LIBS="-LC:/strawberry/Aspell/lib -laspell"

Cheers,
Rob