It's possible that the Data tab is disabled due to certain settings or restrictions in your Excel program. Here are some possible solutions to try:

1. Check if the worksheet is protected: If the worksheet is protected, it may prevent you from accessing certain tabs or functions. To check if the worksheet is protected, go to the Review tab and see if the "Unprotect Sheet" button is available. If it is, click on it and enter the password if prompted.
   
2. Check if the workbook is shared: If the workbook is shared, it may also restrict access to certain tabs or functions. To check if the workbook is shared, go to the Review tab and see if the "Share Workbook" button is selected. If it is, click on it and uncheck the "Allow changes by more than one user at the same time" option.
   
3. Check if the file format is correct: If the file format is not compatible with Excel 2007, it may cause certain tabs or functions to be disabled. Make sure that the file format is in .xlsx or .xlsm format.
   
4. Check if the add-ins are disabled: If the Data tab is still disabled, it may be due to certain add-ins that are disabled. To check if the add-ins are disabled, go to the File tab, click on Options, and select Add-Ins. Check if any add-ins are disabled and enable them if necessary.

Regarding the "group" designation attached to the file name at the top of the worksheet, it shouldn't affect the functionality of the Data tab. However, if you're still having issues, try removing the group designation and see if it makes a difference.