Dedoimedo posted a guide presenting several tips and tricks for solving common Xen problems, including missing modules, bad environment variables, Python site packages, Python versions, wrapper scripts, and more.

When the karma takes a turn for the worst, your virtualization experience may turn sour. If you're a fresh new user of the Xen technology, you may learn the hard way that Xen error messages are extremely verbose and not quite useful, unless you're a Python developer. With a verbose trace and cryptic references to internal function calls, the errors can actually detract you from what are inherently simple and easy-to-solve problems.

While I'm no expert on either virtualization or Python, I've come across a handful of common problems that take only a few short minutes to resolve, but may seem like an eternity to less knowledgeable users. P.S. I am an expert, but it is usually better to claim you are not, because 1) errors are excused then 2) you can afford to fail 3) people love humility and all that underdog attitude. Anyhow, let me help you enjoy Xen.

  Troubleshooting common Xen problems