AutoCAD VB :: Plot Multiple Drawings Using VBA

I am trying to write some VBA code to print several drawings present in a folder.

I am not a VBA expert. I wrote some little macros in excel but it is the first one in Autocad.

I have a small code that opens a drawing, counts it, closes it and then loops for other drawings.

I have a code that print a drawing by defining some printing parameters.

Separately, both work. But when I call the second one into the loop, I get a error:

"Run-time error '-2147418111 (800100001)':

 Automation error

 Call was rejected by callee."

I'm using Windows 7 and Autocad 2012.

See my code below:

Option Explicit
Dim filename As String
Dim filepath As String
Dim full_filename As String
Dim i As Integer
Sub print_trial()
[Code] ......