(VBA) Run-time error '91' Object variable or With block variable not set?

Question

What does this error mean and what is the solution in VBA?

Run-time error '91'

Object variable or With block variable not set

This error occurs with the code, I'm not finding which exactly causing the error :

The declarations in a module

Public DGroup As DUOSObjects

Public DObj As DUOSObject

This the line with error :

DObj.Properties("Percent").Value = Credits

Answer 1

Most likely you haven't actually created the object.  Using Dim or Public to *define* it doesn't make it exist.

Set DObj = new DUOSObject

will create it.  You still need to define it as you have.

Answer 2

Try:

With DObj

.Properties("Percent").Value = Credits

End With

or

With DObj.Properties("Percent")

.Value = Credits

End With

I can't give many more suggestions without seeing this DUOSObject class.