Step 1. Locate the sub procedure called "OLEObjectsAddFromPicture", inside the "RichTextBox" module.
Step 2. Right Click the Variant parameter called "Format".
Step 3. Select "Definition" from the menu.
Step 4. Notice that VB jumps to a parameter of a completely different procedure called "SaveFile".
Step 5. Notice that the type of this parameter is "defined" as an emumeration not a variant:

Public Enum RtfLoadSaveFormatConstants
RtfLoadSaveFormatRTF = 0
RtfLoadSaveFormatText = 1
RtfLoadSaveFormatUnicodeText = 2
End Enum

6. Now, edit the parameter inside SaveFile, from "Format" to "fmt".
7. Navigate back to "OLEObjectsAddFromPicture procedure, and try again.
8. Notice that you jumped to another procedure this time called "LoadFile"
9. Edit the parameter inside LoadFile, from Format to fmt.
10. Try again, now you finally get the correct procedure with a variant definition.

But, you're still using a reserved definition that somehow can jump out from one procedure to another as another type. In a general use module, it would be better to clear this up. Or be stubborn about it, your choice. There are thousands of lines in the code, but the VBA 6.5 parser caught only a couple dozen.