So i'm sure a lot of people have seen this problem before and answered questions on it before!

When I run Bloodmoon and Tribunal a bunch of errors come up sayin stuff about 'chunk size 10 too big'. Now don't tell me to reinstall Bloodmoon and Tribunal with Tribunal first and Bloodmoon after because i've done that plenty of times. I've patched Bloodmoon as well. If anyone can give me answers to my queery i'd be thankful! <_<

Just reinstall Bloodmoon, don't do anything else. Don't uninstall anything, leave the Morrowind and Tribunal disks in their sleeves and don't bother with the patch for now. Just load the Bloodmoon disk, open Windows Explorer and run setup.exe from that disk.

Done that several times, hasn't worked!

Well that's the cause of this error.

Morrowind and Tribunal have eight weather patterns. Bloodmoon adds snow and blizzard to make ten. It does so, by replacing the relevant Morrowind file...not sure which it is...perhaps the esp. If Tribunal is installed last, weather is set back to eight patterns resulting in this error when Bloodmoon is selected.

When you run the Morrowwind uninstaller, a lot of crap gets left behind, but should be overwritten when you do the reinstall. Maybe this overwrite isn't happening properly. Run uninstall again and, when it's done, manually delete the Morrowind folder and empty your recycle bin. Now reinstall Morrowind, Tribunal and Bloodmoon and see what happens.

Also, if you're on Vista or Win7, it's recommended you install somewhere other than a Program Files directory.

So I have to reinstall the whole game not just Bloodmoon?

In general, you only have to reinstall Bloodmoon.

However, as sort of a test, try installing the entire thing (Morrowind, Tribunal, Bloodmoon and any patches) to a totally different directory somewhere far away (on your desktop, in C:\Games, or on another drive).

That will make sure it's not a Vista/7 issue, and moving your mods/saves over is trivial.