Block Titles

Hey, I'm new to drupal but am absolutely loving it so far. I'm currently developing an online shop using ubercart.
On the right side bar I have a popular products block and a rotor module block.
When using the garland theme they have a title but when I change it to the fixed with minnelli theme and a few other downloaded themes that I have tried, the titles for these two blocks disappear but all of my other titles remain there. How do I get them to show? I've looked in both their blocks configuration and their views configuration and tried putting a title in both seperately but nothing is working.

Thanks for your help.

Benen