Hi
Welcome to group

Yes, Blassic looks very much like Commodore basic
You asked:
> By the way, which download should I do from the blassic.org
site?
> Is it the: "Source and sample programs: Gzipped tar package:
blassic-
> 0.10.0.tgz" ? Should I download that one?

Nop,
You are using Windows Xp so download:

http://www.blassic.org/bin/blassic-0.10.0.zip
(this is actual blassic interpreter)

also you should download:

http://www.blassic.org/bin/reference.zip
(this if reference file where you can sheck command syntaxes)

save those zip-files to your hard drive ( for example to c:\blassic\)
and extract them (XP should be capable for that) if you have problems
with un-zipping use winzip to do that

Yours
Kepu