If it worked yesterday but doesn't today, after you have made changes. Then yes, you have done something 'wrong'.
It could easily be something very simple, but it's hard to tell without seeing the code. I'll happily take a look at it, if you want? Would be best to compare it with the previous version (that worked) too. If that would be useful, then feel free to email to s t r i d e n t u k @ o u t l o o k . c o m (you'll need to remove the spaces)