Ach, don't follow slip's advice :P
Replay help
I've had this problem before, but what you do is right click on the replay, select "Open with..." and select tb.exe from the selection or click "Browse" and find your toribash folder, then select Toribash.
If that doesn't work, try dragging the replay into your Toribash replay folder, which will then save it into your replays. You can then watch it by going to Toribsah and selecting settings from the main menu, then replays.
Mod help
Mods are pretty easy. When you open up the file, it should give you an HTML page with numbers and phrase like this:
****Exported by Worldbuilder****
gamerule
matchframes 1000
turnframes 10
engagedistance 100
etc, etc.
select ALL of that, and then copy-paste it into a new WordPad or NotePad document, not a RICH TEXT, just a plain text document. Save that new text file as whatever the mod is, followed by .tbm
For example, mod.tbm
Make sure you select "all files" when you save the mod, otherwise it will turn it into mod.tbm.txt
Hope this helped!