JavaScript error

Hello,

I think I have a problem with my JavaScript on my computer.
I own a IPB forum and the admin control panel is giving me this error.

Uncaught SyntaxError: Unexpected token } ipb.js:1715
Uncaught TypeError: Cannot read property 'prototype' of undefined acp.menu.js:13
Uncaught SyntaxError: Unexpected token return acp.js:197
Uncaught ReferenceError: Debug is not defined acp.tabs.js?ipbv=71265d14872f69724f4dae6d5b86cd7c: 18
Uncaught ReferenceError: ipb is not defined ipb.lang.js:1
Uncaught ReferenceError: ipb is not defined acp.lang.js:1
body.scrollTop is deprecated in strict mode. Please use 'documentElement.scrollTop' if in strict mode and 'body.scrollTop' only if in quirks mode.
body.scrollLeft is deprecated in strict mode. Please use 'documentElement.scrollLeft' if in strict mode and 'body.scrollLeft' only if in quirks mode.
Uncaught ReferenceError: ipb is not defined acp.jquery.js?ipbv=71265d14872f69724f4dae6d5b86cd7 c:663
Uncaught ReferenceError: ipb is not defined index.php:38
Uncaught ReferenceError: Loader is not defined index.php:63
Uncaught TypeError: Cannot read property 'prototype' of undefined acp.templates.js:12
Uncaught TypeError: Cannot read property 'prototype' of undefined acp.tabbed_basic_editor.js:10
Uncaught ReferenceError: ipb is not defined index.php:670
Uncaught ReferenceError: Debug is not defined acp.jquery.js?ipbv=71265d14872f69724f4dae6d5b86cd7 c:19
event.returnValue is deprecated. Please use the standard event.preventDefault() instead.

IPB staff members and my admin team are saying there is nothing wrong with my admin control panel, it’s something to do with my computer.

What is causing this?
Thank you, I’ve been trying to figure out out for 4 days now.

The way I read it, all of those errors are pointing to broken or outdated code being used in the control panel.