I get an error after opening a new topic

[webtiryaki]

Hi what is causing this error?

forum i want help: https://f1wm.net/

Error
Type of error
Undefined_vars
Error message
2: Undefined array key 7
File
/var/www/vhosts/f1wm.net/httpdocs/Sources/Subs-Post.php
Line
125
URL of page causing the error
https://f1wm.net/index.php?action=post2;board=8;preview;xml
Backtrace information
#0: smf_error_handler()
Called from /var/www/vhosts/f1wm.net/httpdocs/Sources/Subs-Post.php on line 125
#1: preparsecode()
Called from /var/www/vhosts/f1wm.net/httpdocs/Sources/Post.php on line 543
#2: Post()
Called from /var/www/vhosts/f1wm.net/httpdocs/Sources/Post.php on line 2140
#3: Post2()
Called from /var/www/vhosts/f1wm.net/httpdocs/index.php on line 191

[Doug Heffernan]

What mods do you have installed and what is the latest change done to the forum prior to the errors happening?

[webtiryaki]

What mods do you have installed and what is the latest change done to the forum prior to the errors happening?

hello mod installed

Optimus   2.10.6
Google Analytics Code 1.6.1

[Steve]

what is the latest change done to the forum prior to the errors happening?

[webtiryaki]

what is the latest change done to the forum prior to the errors happening?

Hello, no changes have been made other than installing the mod.

[Sir Osis of Liver]

Uninstall the mod.  If that fixes it, ask for help in mod support topic.