To reproduce this issue:

1. Open the attached project
2. Open 'crash scene
3. It has a GO with script attached
4. Script has: "UnityEditor.VersionControl.Asset toCheckout = UnityEditor.VersionControl.Provider.GetAssetByPath(assetPath);" in it
5. Set up local Perforce SandBox server or use any other existing server used for Perforce
6. Connect to Version Control server in Editor Settings (Edit-> Project settings -> Editor)
7. Open 'TryCrash' script in monodevelop
8. Set break point at 'UnityEditor.VersionControl.Asset toCheckout...' line
9. Attach to the editor
10.Play the scene
11.Step over the line it breaks at
12. Hover the mouse over the 'toCheckout' variable until the 'quickview' pop-up menu appears
13. Toggle the little triangle to expand 'toCheckout' and show it's properties & fields in the dialog
14. Unity crashes in mono/mini/debugger-agent.c around line 4660

Captured repro: http://screencast.com/t/UcpwDA6l5