Becuase you're not quoting your fields properly. You should use double quotes. And start seperating your variables from your strings, like so
for($i=0;$i<$columns;$i++) {
print "<tr>\n";
$fname = mysql_field_name($fields, $i);
$field = $fdata[$i];
if(is_null($field)) {
$field = "x";
}
print "\t<td><font face=\"arial\" size=\"2\">".$fname."</font></td>\n";
print "\t<td><font face=\"arial\" size=\"2\">
<input type=\"text\" size=\"20\" value=\"".$field."\" name=\"text\">
</td>\n";
print "</tr>\n";
}
You should also get away from using <font> tags, and start using CSS to control your pages.