I don't know what's up here but whenever I try to install SkyUI I get the following message:

The Publisher could not be verified. Are you sure you want to run this software?

"Unknown Publisher"

I then get the following message:

This report informs you about potential problems with your SkyUI installation.

Fix these problems , then press 'Refresh' to confirm that they're gone.
After all problems have been resolved, you can continue with the installation.

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Problem #1:
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The SKSE scripts are missing.

Potential causes:

* You didn't install the scripts with the rest of SKSE.

Solution:

1. Re-install SKSE. Make sure you extract the 'Data/' folder from the downloaded archive to your Skyrim installation directory.

It says it's something to do with SKSE, but I've had that installed for ages and it's been okay until now. Only this mod doesn't seem to like it.

I assume you use MO as mod manager? Simply skip the message, SkyUI will work nonetheless.