TexMod is incredibly buggy, crashing at the drop of a hat and giving graphical errors galore at the best of times, but in addition the Elona Cartography Made Easy archive is available in several versions, at least some of which are broken. For instance the version linked to from Guildwiki doesn't work for me.
I'd recommend trying a Elona Cartography Made Easy file from some other source before concluding that TexMod wont run on your Vista.
I don't remember where I downloaded my ECME file, but a google search should find alternative download sites for you. For what it's worth my functional .tpf file is 3 808 795 bytes in size, and the CRC32 is B6C1B449.
i'm using home premium on my computer and TexMod works fine. i use the same mod as well...not really sure what the issue might be... Are you using -image?