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Operations Research Models and Methods
 

Frequently Asked Questions

Here are a few questions that I've had to answer from students and other users. Although I try to make the add-ins robust, users often do things that I would never have suspected. If you have trouble look over the list below. Read the section Add-in Basics on this site where there are other frequently asked questions. Also, read the instructions for the add-in you are attempting to use.


Question
When I click on a button on a worksheet a error message, saying "A document with the name 'add-in name' is already open. You cannot open two documents with the same name, even of the documents are in different folders."

Answer
The worksheets in the ORMM CD chapter files and also the demo worksheets have buttons. These buttons are linked to the add-in on the author's computer. To make the buttons connect to the add-in that you have installed on your computer follow these instructions.

For worksheets with buttons, we have included a Relink Buttons command. This command creates new buttons linked to the your Add-in. This usually must be done for each worksheet in the workbook.

The same problem results when there are user-defined functions on the worksheet. In almost all cases the Relink buttons command creates the proper links. If this doesn't work use the Links Command on the Edit menu of Excel. This command allows you to change the links from the author's computer to your computer.


Question
I get an runtime error message. What do I do?

Answer
We have tried to find all errors, but some may still exist. Contact the author with as much information as possible. One way to find the exact source of the error is to go to the Visual Basic Editor by selecting Macros from the Excel Tools menu. In the Project Explorer, click on the name of the add-in. Enter the password 'ppp'. Try to generate the error again. If it occurs again, click the Debug button. The focus will move to the program where the error occurs. If the line simply formats a cell, you can make the line a comment by putting an apostrophe (') before the line. Otherwise copy the line and put it into an e-mail to the author.

VBA sometimes makes errors on international versions of Excel in cases where it won't make the error on the English language version. Tell the author as much about the problem as you can.


Question
I am using a version of Excel 97 or earlier and get an error.

Answer
The add-in were initially created with Excel 97 or later, but changes have added features which are not compatible with Excel 97. Try a more modern version of Excel.


Question
Excel takes a long time to open or terminates unexpectedly.

Answer
One reason may be that you have too many add-ins installed. Only install the add-ins you are immediately using. Also, it is good idea to use only a few worksheets in a workbook and to close any workbooks you are not using.


Question
Excel may fail and say that it can't make a button when the add-in is creating a new form.

Answer
Delete the partial page created and save your work. Shut down Excel and the restart. The problem may go away. A general rule for problems is to shut down and restart Excel.


Question
When I open an add-in (.xla) I get a message warning about Macros.

Answer
You are installing the add-in incorrectly. It must be installed through the Add-ins Command on the Tools Menu. You can also use the OR_MM add-in or OM_IE add-in to install and uninstall add-ins.


Question
When trying to create a math programming model, I get an error message regarding the Excel Solver.

Answer
Be sure the Excel Solver is installed. If it is the word Solver appears on the Tools menu. If the Solver does not appear the Solver add-in is probably not installed. It comes on the Excel or Microsoft Office CD, but it may not be installed with a Typical installation choice.

If the Excel Solver is installed and you get the message, open the Solver dialog before trying to build the math programming model. This will establish a link to the Solver and the problem should be resolved.


Question
I create a math programming model or other type of model that creates a named worksheet. I changed the name of the worksheet and now it won't work.

Answer
You should not change the name of a worksheet that was created by the add-in. Often the add-in names ranges on the worksheet with a prefix that is the same as the worksheet name. If you change the worksheet name the add-in cannot discover the prefix.



 

 

 

  
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Operations Research Models and Methods
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by Paul A. Jensen
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