Sorry, I don't have much more info than it is a horror movie and the people are trapped inside a building... hotel I think, and they pour a liquid over the doors. Can't remember if it is a red liquid or a blue liquid.

I hope you can help me Quinn my husband and I would like to see this one again. I think it was from the '90s.

Sorry J_9, this one isn't familiar to me. If you don't find the answer here, try the I Need to Know board at IMDb. Good luck!

Thanks Quinn, I knew it was a long shot with such few details.

It sounds vaguely familiar, but I have an episode of Special Unit 2 stuck in my head.

Special Unit 2 has an episode where they attend Kate's High School Reunion and creatures seal them in the school with a reddish resin.
Special Unit 2 on TV.com

It was a movie that we rented way back in the early 90s. I think there were vampires involved, but I can't remember.

I know this one - it's Demon Knight, came out in 1995

Yay!