This from the Fonda's website:
We're very sorry to announce that Trent is ill, and on his doctor's orders we will not be able to perform tonight's show at the Henry Fonda Theater. This is the only information we have at this time, we're posting this early announcement as a convenience for those of you who had plans to attend. Reimbursement details will be posted as soon as we figure them out; likely within the next 24 hours. We wish this wasn't necessary and we're very sorry for the inconvenience. Thank you for your understanding.