How can I debug System.DllNotFoundException when missing DLL is not reported?

I'm maintaining a small .NET application that loads a GeckoFX webview in a .NET shell. It works on the vast majority of machines but on one specific 64 bit Windows 7 machine it reports the following exception:

Description:
 Stopped working

Problem signature:
 Problem Event Name:   CLR20r3
 Problem Signature 01: monoclecatdesktop.exe
 Problem Signature 02: 1.0.0.0
 Problem Signature 03: 4db67550
 Problem Signature 04: Skybound.Gecko
 Problem Signature 05: 1.9.1.开发者_JAVA百科0
 Problem Signature 06: 4db625ff
 Problem Signature 07: 54
 Problem Signature 08: 87
 Problem Signature 09: System.DllNotFoundException
 OS Version:   6.1.7600.2.0.0.768.3
 Locale ID:    4105

I tried using Dependency Walker to locate the missing DLL, but nothing jumped out at me. I am pretty new to Windows programming so I'm not sure where to begin debugging this. Any advice is appreciated!

---

If you can use process monitor. Put on a filter excluding everything but your process. Then look for results that aren't SUCCESS.