iTunes got an error: An error of type 9037 has occurred

My playlist sometimes produces this error on play from a Applescript:

"iTunes got an error: An error of type 9037 has occurred"

It happens if it is a smart playlist or a playlist. I thought it may be due a bad podcast reference as there was one mp3 podcast file that couldn't be found.

Any assistance in how to solve this or how to investigate further would be greatly appreciated.

Jeff