Mail & Mime_Mail classes corrupts tar.gz attachments sending them

Hello everybody! Please, help me! I have created a web-site using php. All its data are stored in MySQL database. I also wrote scripts for this site's administration area. An operator in administration area inputs all changes in the temporary tables, then pushes a button that executes script which copies all the data from that modified temporary tables to the 'visible' ones. (The latter makes my site's contents visible for any visitor -- now for my BOSS). So, in the moment after that copying I need the script send me new tables via e-mail. I form sql dump, compress it using PEAR's Archive_Tar->addString(...) in .tar.gz format and always can download it, decompress and execute. Now I need not to download it, but receive via e-mail. I send it as attachment using Mail_Mime and Mail. When I receive that mail, NO archiver can decompress it -- CRC failed, invalid directory and so on (tested on WinZip, 7-Zip, ICEOWS). Tell me please what may be problem? Or what do I wrong? Looking forward to hear from your soon. Sincerelly yours, Valeriy Krizhevich.