VFP9 WinXP SP1/2

My VFP 9 application (an EXE) is behaving differently on different computers, all running XP, and all accessing the same database located on another machine in the lab.

On two of the computers, the application starts up just fine, and presents the user with the startup form. On 3 other computers, 80% of the time it starts up fine, and around 15 to 20% of the time it does not. When it does not, it presents a series of 45 error messages that is always the same each time it occurs. The error messages indicate a problem during application initialization. The program appears to be having a problem in the SetAllProp method of the TxtBtns control in the Wizbtns.vcx library that comes with VFP.

This method is a recursive function that goes through all of the containers of the form, and sets the Enable property of the enclosed controls to either enabled or disabled.

I get two types of error messages. Both are error #1924 ("name" is not an object). The first says that a parameter being passed into the method is not an object. These messages indicate a line # in the SetAllProp method. Sometimes the indicated line does have a reference to the object parameter; sometimes they do not.

The second kind of error message shows a SELECT statement, followed by the error #1924, and a line # in the SetAllProp method. But, the SELECT statement is not in the SetAllProp method. Rather it is the RowSource for a listbox elsewhere on the same page of the form.

This bug is proving particularly difficult to debug. I have VFP 9 installed on the two computers where the problem does not occur. I do not have VFP 9 installed on the computers where it does occur.

I have tried using DebugView from SysInternals on the computers showing the problem. I have inserted OutputDebugString messages to monitor the program. However, when DebugView is running, the problem does not occur.

On one of the computers having the problem, I have stopped the WindowsUpdate program (which is running in the background), and the problem seems to have gone away. However, on a 2nd machine with the problem, stopping WindowsUpdate did not stop the problem.

I would appreciate any suggestions on how to solve this problem.

Thanks,
Jim