i had similar situation.
In file qa-markdown-editor.php
i did commenting this strings:
//$js = file_get_contents($this->pluginurl.'pagedown/markdown.min.js');
//if (qa_opt('md_enable_image_upload')) {
// $js = str_replace("<!--REPLACEMENT_UPLOAD!>", '<div><form enctype="multipart/form-data" id="qa_imageupload_form" name="qa_imageupload_form" action="upload.php" method="POST"><input type="file" name="qa_imageupload_file" id="qa_imageupload_file"><input type="button" value="Upload" onclick="javascript:qa_imageupload();" name="qa_imageupload_submitbutton" id="qa_imageupload_submitbutton"></form><div id="progress"></div></div>', $js);
//}
//$html .= '<script type="text/javascript">'.$js.'</script>' . "\n";
//$html .= '<script src="'.$js.'"></script>' . "\n";
and then added this string:
$html .= '<script src="'.$this->pluginurl.'pagedown/markdown.min.js"></script>' . "\n";
and also in file markdown.min.js
this :
<!--REPLACEMENT_UPLOAD!>
replace on this:
<div><form enctype="multipart/form-data" id="qa_imageupload_form" name="qa_imageupload_form" action="upload.php" method="POST"><input type="file" name="qa_imageupload_file" id="qa_imageupload_file"><input type="button" value="Upload" onclick="javascript:qa_imageupload();" name="qa_imageupload_submitbutton" id="qa_imageupload_submitbutton"></form><div id="progress"></div></div>
and this proplem was resolve
good luck