Debug symbols when attaching to a Process

I've compiled my app and I can debug it when I hit F5 from SharpDevelop.

I move the app (.exe + .pdb + config and other files needed, I'm confident that I'm not missing any needed file/configuration) to an other folder and I'm getting a strange crash - that I need to debug - when launching the app from there (after a certain sequence of actions, but the application issue is not relevant for this question).

So I start the .exe from the folder and I Debug>Attach to Process from SharpDevelop, but it does not find the Debug Symbols!

Please, help me.

Thanks