This only fixes the "Unable to find event: Capture" error (as far as I know).

How to fix the error:

Step 1: Navigate to this directory: C:\YourServerFolder\oxide\plugins\
Step 2: Open "CaptureTheFlag.cs" in Notepad or another text editor
Step 3: Press "CTRL + F" on your keyboard and type "Capture the Flag"
Step 3: In line 15, change "Capture the Flag" to "CaptureTheFlag" as seen below

Default:
[Info("Capture the Flag", "k1lly0u", "0.1.63")]

This is what the line should look like to fix the error:
[Info("CaptureTheFlag", "k1lly0u", "0.1.63")]


This worked for me. Hope it helps you too!

Merged post

@k1lly0u