userform with looping code

Here are some of the issues that I have encountered:
Also note at work, I will be using excel 2003, so I may need to combine the "Lookups" & "Sheet1" worksheets together, in order for the data valadation to work properly, but I am experiencing the following issues using excel 2010.

1. Changing worksheet "Sheet 1" name. I attempted to try to change the name to "Input Attendance" and then went into the code and changed "Sheet 1" to "Input Attendance" in the spot that I seen it, but it didnt seem to work.
   
2. Changing the employees names in the "Lookups" sheet. I tried to paste over the names in the list using the real life employees and everytime I do, it will allow me to pick two names and then the drop downs no longer work. The name range is still the same so I am not sure why this would be an issue? All I am doing is pasting data over the existing names. But as the company has a large turnover rate, we will need to update this list frequently.
   
3. I need to delete all entries in the Log, so that I can start from scratch, and I am experiencing some difficulties doing this, by using the "amend rota" button. I have also tried to just delete the records straight from the log.

Until I get this fixed I wont really be able to tell what other bugs there are.