Abby, I think the problem may be that 1) Mudcat is running very slowly, and 2) When you embed the tune, the file has to be loaded from somewhere else on the site. It did do something - it told everyone's computer to "go get the sound file, open the program to play midis and play it."In short, it takes longer to load a thread and requires more resources from a person's computer to do so
The colors - I'm not sure what happened with the font color. You used FF0000, which looks like standard red. A nice dark one is E60500. I don't think it's possible to change the background color because of the way the individual messages are compiled to form a web page. You could do a table with invisible borders.
In any case, I love the song and the tune. We do the Clancy Bro's anglicised version. I once mentioned this to a famous Scots singer, whereupon he said something like "Oh, I'm sorry." I do love Hamish Henderson's original words, even if I can't wrap my tongue around them.