Dear Deborah
Ok - I can sense your frustration level building! 
Here are some things you can do to narrow down or eliminate what the actual problem could be:
1. Using Explorer, go to the directory where they keep their QL files. There should be two files for every worksheet they have - an .xls file and a .dnk file. (Ensure you are looking at 'all files'. If there is only the .xls files, then possibly the corresponding .dnk files did not get copied over to their local drive as they should have. Both types of files must exist in the same directory in order for QL to use them effectively.
2. When they open and save their QL worksheets, they must use the QL options to do so, not the Excel File Open & Save commands.
3. Ideally, Excel should exist on the same drive where you want to install QL, and it should be there prior to installing QL.
4. Can you create a brand new worksheet by going through the steps in QL? (Assuming you are working with an already initialized dataset) For example, (I will use GL):
a) Open QL and, from the main Excel Toolbar 'QuikLink' menu option, select 'Link' and define a new link (leave all default values in the Link Definition window as they are - just give the link a name such as 'gldata' if using the GLDATA@@.SAM dictionary.) then click Accept.
b) Now, select the 'Read' option from the QuikLink menu
c) Select 'Read Formulas or Values' and click OK
d) Select the newly created 'gldata' link and click OK
e) Now, let's select the ACCT, DEPT, DESC & BAL from the list of fields at the left, then click OK
f) Now you should be at the 'Quik Link - Read Values or Formulas' dialogue. Make sure that on the right-hand side, the option for 'Formulas' is selected, as this is what will determine a worksheet that can be updated in the way that you want. Click GO.
g) You should now see all the GL accts/depts and their balances on the worksheet.
h) Using the QuikLink toolbar menu option, now select File Save, and save the QL file. Note that two files will actually be created during the QL save process, the expected .xls file and a corresponding .dnk file. BOTH of these files must exist in the directory where they keep their QL workbooks.
i) To test the success of the save, exit out of this worksheet and Excel/QL now, and after going back into QL, select File Open from the QL menu option, and open the newly created QL workbook.
If you have no trouble creating and using a new worksheet, but still have problems when using a previously created QL file, then you may want to take a look at the QL manual, Chapter 1, page 1-12 for Redefining the Excel Links (it won't hurt) and also you may want to try just redefining the actual QL Links being used in the problem worksheets.
Hope this helps.
Regards,
Softrak Support