For a working download button (in IE under Windows ) for text files in the survey of version 1.5.3 you should insert the following headerinfo in /mod/survey/download.php starting at line 194:
.
194 // Otherwise, return the text file.
195
196 // Print header to force download
197
198 header("Content-Type: application/download\n");
199 header("Content-Disposition: attachment; filename=$downloadfilename.txt");
200 header("Expires: 0");
201 header("Cache-Control: must-revalidate, post-check=0,pre-check=0");
202 header("Pragma: public");
199 header("Content-Disposition: attachment; filename=$downloadfilename.txt");
200 header("Expires: 0");
201 header("Cache-Control: must-revalidate, post-check=0,pre-check=0");
202 header("Pragma: public");