Not sure why you would see the results you are seeing.
I would suggest not using FSO for this though

Also no need to check to see if the file need to be created or not simply use the build in VB method

Code:
FileNumber=FreeFile
Open Filename for Append as #FileNumber
This method will create the file if it does not exist and append to it if it does.

To write a line to the file you would use the Print # method
Code:
 Print #FileNumber Now & ": " & message
    Close #FileNumber