need help to solve internal error at version 2.13.1

[polliwog]

INTERNAL APPLICATION ERROR while upload attachments.

There is no more information I can track to solve problem.

When I attach any file (even it is small image like 5kb), it shows the error message and fail.
additional message is press go back button if you want to go back. and solve problem to fix this issue without any hint.

below is my config setting.

--- Attachments / File Uploads ---
$g_allow_file_upload = ON;
$g_file_upload_method = DISK;
$g_absolute_path_default_upload_folder = 'E:\mantisfile';
$g_max_file_size = 5000000;

$g_preview_attachments_inline_max_size = 256 * 1024;
$g_allowed_files = '';
$g_disallowed_files = '';

and below is php check result.

file_uploads On
max_file_uploads 20
upload_max_filesize 2M

What more I need to check and fix to use attachment?

// added after posting. sorry.

after checking some more, I found out add notes are not working at all.
and found another case. I don't know how this is changed but sometimes mantis show one of two errors.

1. INTERNAL APPLICATION ERROR

2. SYSTEM WARNING
'count(): Parameter must be an array or an object that implements Countable' in
'E:\Apache24\htdocs\mantis\core\commands\IssueNoteAddCommand.php' line 246

I really need any hint to find out why and how to solve it.
Thank you.

[atrol]

I assume this one is fixed https://www.mantisbt.org/bugs/view.php?id=24413