Reading the Registry using VB6

The posting from dhaest on reading the registry in VB is the ONLY one I have found that actually works!  SO, I am curious as to why it is necessary to Dim a Byte array as  the receiving area for the registry key? It DOES seem to be necessary, for if I specify a String variable (adequately sized by Stringvar = String(1024,0) for example), the call to RegQueryValueEx  fails in my WORD/VBA macro (Office 2000), crashing WORD every time ("An error log has been created" --- sez Windows 2000, but it's nowhere to be found, of course; Win98 indicates an invalid operation, suggesting a write-protection fault).   In my case, I know that the key value is a REG_SZ, and in fact, a call to RegQueryValueEx with a null 'lpData' returns the data type as REG_SZ  and returns the required buffer size (verified as correct, by looking at the Registry) --- BUT when I then pass the String variable as the 'lpData' --- CRASH, every time.  Why?  Clearly, there are things about the "inner" workings of VB/VBA that I do not understand.  I'm feeling very fortunate to have found this posting after days of frustration, so I would welcome an explanation as to why a String var cannot be used --- or what it takes to use one in a "acceptable" way!

My recommandation: answered by dhaest

Private Sub Form1_MouseDown(ByVal Button As Integer, ByVal Shift As Integer, ByVal X As Single, ByVal Y As Single)
    Dim KeyVal As String
    KeyVal = GetSetting(Application.Name, "HKEY_LOCAL_MACHINE\SOFTWARE\XXXSOFT\", "XYZSOFT_HOME", "")
End Sub

I found Dhaest's code solution to be Extremely Helpful.