For attachments, mb_send_mail is not supported. mail is supported. why?

An error occurred while sending attachments. mb_send_mail is not supported. mail is supported. why? You are in a hurry. Thank you. the following is my program: & lt ;? Php $ from & nbsp ;. = & nbsp; & quot; & nbsp; & lt; kei @ lx94 & gt; & quot; $ to & nbsp; an attachment issue occurs. mb_send_mail is not allowed. mail is allowed, why?
Worried,
.
Thank you.
The following is my program:



$ From. =" ";

$ To. =" ";

$ Subject = "ァルテス ";
$ Body = "ァ テス ";

$ Filename = "/work/cgi-bin/prs/test.txt ";
$ Att_files = "/work/cgi-bin/prs/zookeeper program contains zookeeper .txt ";
// $ Mine = "js ";

// Send_mail2 ($ to, $ subject, $ text_body, $ headers, $ html_body = "", $ att_names = "", $ att_files = "", $ file_types = "");
/*
If ($ filename ){
($ Attach = file_get_contents ($ filename) Or die ("Open Error: $ filename ");
$ Filename = basename ($ filename );
$ Ret = Attach_Mail ($ from, $ to, $ subject, $ body, $ filename, $ attach, $ mine );
} Else {

}
*/
$ Ret = send_mail ($ to, $ from, $ subject, $ body, $ cc = null, $ bcc = null, $ filename );
// Echo $ ret;

Function send_mail ($ to, $ from, $ subject, $ body, $ cc = null, $ bcc = null, $ attachment = null)
{
If ($! = "" & Isset ($ )){
$ To = str_replace ("", "", $ );
$ To = str_replace ("\ t", $ );
}
If ($ cc! = "" & Isset ($ cc )){
$ Cc = str_replace ("", "", $ cc );
$ Cc = str_replace ("\ t", $ cc );
}
If ($ bcc! = "" & Isset ($ bcc )){
$ Bcc = str_replace ("", "", $ bcc );
$ Bcc = str_replace ("\ t", $ bcc );
}

// Set the parameters for reading and writing texts
$ Body = "BCC: $ bcc \ r \ n $ body \ r \ n ";
$ Body = "CC: $ cc \ r \ n $ body \ r \ n ";
$ To_tmp = join ("\ r \ n", explode (",", $ ));
$ Body = "TO: $ to_tmp \ r \ n $ body \ r \ n ";

Mb_language ("Japan ");
Mb_internal_encoding ("EUC-JP ");
Mb_detect_order ("ASCII, JIS, UTF-8, EUC-JP, SJIS ");

// From original vertex
// $ FromName = mb_encode_mimeheader (mb_convert_encoding ($ FromName, 'jis ', 'auto '));
// $ Header. = 'from: '. $ FromName.' <'. $ FromMail.'> '. "\ r \ n ";
$ To = "testmail @ lx94 ";