Internal Service Error (500) Bitnami Redmine: Error -Mysql2::Error: Subquery returns more than 1 row

[rajubushanam]

I am using the following versions:

Bitnami Redmine version: 2.3.1.

Ruby version : 1.9.3

Rails version : 3.2.13
I have installed a plugin called Redmine impasse version: 1.3.0.

It is implemented across multiple projects. Only in one of the project, when it is opened, it comes up with an Internal Service Error 500. It works fine in all other projects. It worked fine for a while in this project. But suddenly this issue came up.

After looking at the production log I found the following error,

ActionView::Template::Error Mysql2::Error: Subquery returns more than 1 row
Can anyone help me out on this?