Got a Drupal6 install, and I'm using a webform to collect some data. The webform has a path alias set on the edit page as 'contact_us'. The issue that I can't figure out (and hard to reproduce) is from time to time, some users end up on the page 'node/'. Seems like that is a possible failure trying to find the alias or system path.

Any one seen this before? Any suggestions on some places to look or to why this is happening?

Regards