To clarify on what
@Squidl said...
Uninstall RuneMate again, and check if theres still files at the following locations:
1. C:\Users\<your username>\RuneMate
2. C:\Program Files (x86)\RuneMate
If any of these folder still contain files, delete all of them.
Then simply redownload and reinstall RuneMate from
Download | RuneMate
If this didn't help, please post the latest Spectre.txt log contents in this thread.
You can find the logs at C:\Users\<your username>\RuneMate\logs