Form appears locked 2nd time VB6 dll runs

Please help me figure this out.
I have spent almost 2 weeks stuck on this.

I use a group of projects - most use vba code and vb6 dlls without forms, 2 of them use vb6 dlls that show forms and produce a drawing.

The projects worked in AutoCAD R14, but we are now upgrading to 2004.

I use menus with AutoLISP to unload the currently loaded project, load the desired project, and run the appropriate macro.
After some modifications, all projects work great except for the 2 that show vb6 forms.

The problem: The first time I run a project that uses VB6 forms, it works.
The second time I run a project that uses vb6 forms, the form appears to be locked!
It does not respond to the mouse or to the keyboard keys, except if the form has a Cancel button, the Esc button closes the form. Once the form is closed, AutoCAD and the projects without vb6 forms work fine.
Any subsequent attempts to run a project with vb6 forms respond the same way - the form appears to be locked.

I have set all AutoCAD related object variables in my dlls to Nothing when I am done using them, but this still happens.
I tried keeping track of when classes are initialized and terminated - the main class and the forms terminate upon unloading the vba project. Is this causing my problem?

Any suggestions would be appreciated - I am close to pulling my hair out over this!

 

Hmmm....first you don't need to unload/load projects in 2004. You can have
as many loaded as you want but that isn't causing your problem. Are you
unloading the form and killing the object that holds reference to your DLL?

Post your code that loads/unloads the projects and the code that calls the
DLL. Then wew can see what might be causing your issue.

 

I have a set of 11 projects, and some of them have multiple UserForms, will keeping them loaded use up too much resources?

Here is the code I am using - I am including VBA code from 2 projects, since I revised one, but both have the same problem:

___AutoLisp (to load and unload projects and call macros)___


(defun NEWPROJ ( ProjName MacroName / VBName) ;VBName is a local variable, ProjName and MacroName are arguments
(setq VBName (vl-bb-ref '*VBName*)) ;Retrieve *VBName* global value from the blackboard

(if (= VBName (findfile "acadmsr.dvb")) ;If acadmsr is currently loaded, call EndRafter to release object references before unloading it.
(COMMAND "-VBARUN" "MENUOPTIONSMODULE.ENDRAFTER") ;rafter project loaded - run EndRafter.
)

(if VBName (command "vbaunload" VBName)) ;If a VBA project is loaded, unload it
(setq VBName (findfile ProjName)) ;Set global *VBAProjName* to the full path name to the file to open.
(vl-bb-set '*VBName* VBName) ;Write *VBName* global value to the blackboard
(if VBName
(progn
(command "vbaload" VBName) ;Load the current VBA project
(COMMAND "-VBARUN" MacroName) ;Run the macro
)
)
(prin1)
)


(defun c:EWCOLUMN ()
(NEWPROJ "acadewc.dvb" "MENUOPTIONSMODULE.DETAILEWCOLUMN")
)


(defun c:MSRAFTER ()
(NEWPROJ "acadmsr.dvb" "MENUOPTIONSMODULE.MULTISEGRAFTER")
)


(defun c:NEXTSEG ( / VBName) ;VBName is a local variable
(setq VBName (vl-bb-ref '*VBName*)) ;Retrieve *VBName* global value from the blackboard
(if (= VBName (findfile "acadmsr.dvb"))
(COMMAND "-VBARUN" "MENUOPTIONSMODULE.DETAILNEXTSEG") ;rafter project loaded - run DetailNextSeg.
(princ "No rafter is currently being detailed.\n") ;rafter project not loaded - display message.
)
)


(defun c:ENDWALLRAFTER4MS ()
(NEWPROJ "acadmewr.dvb" "MENUOPTIONSMODULE.ENDWALLRAFTER")
)


___VBA for project 1_____

Option Explicit
Public MSR As MSRaf.Detail


Public Sub MultiSegRafter()
'Change the current directory to the AutoCAD directory
ChDir ThisDrawing.Application.Path

Set MSR = New MSRaf.Detail
Set MSR.AcadApp = ThisDrawing.Application
MSR.MultiSegRafter
End Sub


Public Sub DetailNextSeg()
'Change the current directory to the AutoCAD directory
ChDir ThisDrawing.Application.Path

If MSR Is Nothing Then
MultiSegRafter
Else
MSR.NextPiece
End If
End Sub


Public Sub EndRafter()
'Set MSR.AcadApp to Nothing, then set MSR to Nothing.
MsgBox "MSR = Nothing"
Set MSR.AcadApp = Nothing
Set MSR = Nothing
End Sub


___VBA for project 2_____

Option Explicit
Dim EWC As DetailColumn


Public Sub DetailEWColumn()

'Change the current directory to the AutoCAD directory
ChDir ThisDrawing.Application.Path

Set EWC = ThisDrawing.Application.GetInterfaceObject("EWColumn.DetailColumn")
EWC.EndwallColumn ThisDrawing.Application
End Sub


Thanks in advance.

 

Some new info on the problem:
I was using a messagebox on the Initialize and Terminate events of some of my classes to see when they were being created and destroyed. I removed the messageboxes, and now DetailEWColumn in project 2 works fine.
However, Project 1 still causes a problem. After the first time I run MultiSegRafter, whether I run MultiSegRafter again, DetailNextSeg, or DetailEWColumn, the vb6 form appears to be locked.
Projects that show vba UserForms continue to work.

Again, thanks for any suggestions.

 

Mike, thanks for your suggestion.
It got me thinking in a different direction, and sometimes that is all it takes.

I figured out that the problem is being caused by messageboxes being displayed while an AutoCAD drawing is being edited.
(Both the messageboxes and editing the AutoCAD drawing are done from inside the VB6 dll.)
This also causes the AutoCAD VBA editor to lock up, although AutocAD keeps working.

If anyone knows why this is a problem, I would be very interested to hear it.