File upload error - no mime boundary found after start of file header

I am working on a site that handles a lot of file uploads. Occasionally the following error will be thrown: shell httpd: PHP Warning: File Upload Error - No Mime boundary found after start of file header in Unknown on line 0 Now I figured this was probably a browser bug rather than a PHP bug but a grep of the last few log entries shows a variety of browsers (see end of this message) The guts of the form is: <form enctype="multipart/form-data" action="genie_upload.php" method="post" name="uploadform"> <input type="file" name="userfile" size="30"> <input type="submit" value="Upload" onClick="return validateform()"> </form> Any ideas what could be wrong please? rfc1867.c makes no sense to me. Thanks. David recent browsers: Mozilla/4.73 [en]C-SYMPA (Win95; U) Mozilla/4.06 [en]C-gatewaynet (Win98; I) Mozilla/4.0 (compatible; MSIE 5.01; Windows NT 5.0) Mozilla/4.0 (compatible; MSIE 5.0; Windows 98; DigExt) Mozilla/4.0 (compatible; MSIE 4.01; Windows 98) Mozilla/4.0 (compatible; MSIE 5.0; Windows 98; DigExt; MSN 6.0) Mozilla/4.0 (compatible; MSIE 5.0; AOL 6.0; Windows 98; DigExt) Mozilla/4.0 (compatible; MSIE 5.0; Windows 98)::ELNSB50::00004110028001e0027a016c000000000503002a00000000 Mozilla/4.0 (compatible; MSIE 5.5; Windows 98; Win 9x 4.90) Mozilla/4.0 (compatible; MSIE 5.5; Windows 98; Win 9x 4.90) Mozilla/4.0 (compatible; MSIE 5.0; Windows 98; DigExt) Mozilla/4.0 (compatible; MSIE 5.0; Windows 98; DigExt; AIRF) Mozilla/4.0 (compatible; MSIE 5.5; Windows NT 5.0) Mozilla/4.0 (compatible; MSIE 4.01; Windows 98)