Modules & VBA :: Database Quits For No Apparent Reason

I'm having a weird problem in VBA on a button click. For no apparent reason the database closes itself. No error, no crash - it just closes. I've compacted and repaired it, recompiled it, but still exactly the same. The strange thing is, if I insert a blank message box at the point in the code where it quits, everything then works perfectly!

Also, if you leave Text4 empty so that it displays the message box telling you to enter a code to start, when you then enter something the next time it also works perfectly. Somehow the process of displaying the message box seems to fix whatever the problem is. I've tried pausing the code at that point, I've tried changing the focus to a different control or another form.

Here's the code:

Private Sub cmdReqLookup_Click()
Dim strTaleoReq As String
Dim strTaleoID As String
Dim intIDMatches As Integer
Dim strContractID As String

[Code] .....

'This is where the database quits. If I add a message box here, it then runs perfectly!

'Disable button
Me.cmdReqLookup.Caption = "Please wait..."
Me.cmdReqLookup.ForeColor = vbRed
Me.cmdReqLookup.Enabled = False
Me.Refresh
ScriptHold (1)

[Code] ....