[tag][/tag] BB Code doesn't work?

[Vitreous]

As the title says, this BB code returns a database error when you click on it:
[NOPARSE][tag]meguiv[/tag][/NOPARSE]

Here's the code for real: [tag]meguiv[/tag]

I'm not exactly sure what it is supposed to do when you click on it: I was hoping it would return a search on the tag.

 

[IdolFun]

I was hoping it would return a search on the tag.

That is what it should do.

Don't know why it is broke:dunno: