[Dxbase] crash bug in DXB2007

[Chris Codella, W2PA]

I happened across this bug today - repeatable - works every time for me.

1. click on callsign field in log
2. click the "find" icon
3. type in a call you expect to find, click "find next" button
4. without closing the "Find" window, click the previous QSO icon in the 
summary window
     (it probably shouldn't let you do this)
5. close the previous QSO window (using the "X" window control)
6. close the Find window (same way)
7. Bang!  DXBase exits completely!   It warns to initialize tables next 
time you start up.

It also crashes if, in step 3, you simply click on a filled-in log 
entry.  You can even skip step 3 entirely.  It seems that once you have 
both the find window and the previous QSO windows up, closing them 
crashes DXBase.

73,
Chris, W2PA