>VFP9 WinXP SP1/2
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>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.
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>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.
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>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.
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>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.
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>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.
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>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.
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>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.
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>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.

If you're not already doing so, run your .EXE from local HDs rather than a single copy on the "server" machine.

Try disabling AV on all systems to see if that makes a difference.

Run full AV scans on the problem computers and antispyware such as Ad-Aware or Spybot.

You can take a look at Re: Write-behind caching. Still need it off? Thread #994207 Message #994323 for some general ideas. XP is sensitive to DNS configuration, check out http://support.microsoft.com/?id=291382