MissingSourceFile - how to debug?

Hi all - a search for this kind of problem only brought back results for specific solutions to the gem or library in question.

I'm getting the following error appear at certai times, like when trying to refresh my gems specs:

[code]You are missing some libs #<MissingSourceFile: no such file to load -- bdb>[/code]

How would I go about debugging this?

- I do not have this gem installed - I cant see where my app is using search (search for bdb yields no results)

Any ideas?