What error reporting are you talking about? How can I reproduce the issue?

The tweaker should remember the width upon restart. What OS are you using?
Also, please check whether the following registry value is being created:
last_taskbar_width (DWORD) in:
HKEY_CURRENT_USER\Software\7 Taskbar Tweaker

There's no registry option for this tweak, as far as I know.

Duplicate:
http://tweaker.userecho.com/topic/145644-taskbar-i...

The last time I've checked, UltraMon used it's own implementation of the taskbar, and there were no grouping or combining.

A duplicate of:
http://tweaker.userecho.com/topic/343539-remove-po...

Please tell me your location, I'll try to sort it out.

You're referring to this link, right?
http://rammichael.com/7-taskbar-twekaer-and-window...
Are you located in one of the following locations?
China, Japan, Hong Kong, Korea, Thailand, Taiwan.
The hosting had issues with those before.

Currently, Windows 8.1 Update 1 (and the equivalent server version) are not supported.
More information: 7+ Taskbar Tweaker and Windows 8.1 Update 1