MIME coding & flags for sending a .csv or Excel file

[jason corbett]

I am sending Excel and .csv files via MIME and it appears that the file is created on 
the server with the needed data, but when the script is supposed to email a copy, I am 
getting blank .csv files. 
 
My question:
 
Do I need to identify the file in MIME as a .csv or Excel?
Are there flags that I need to set?
 
Thanks,
JC