Scenario creation question

Hi,

I am running a script in vugen and it works fine. I then run it in controller (run until completion) and it completes fine. However, for the same number of users I set the duration to 10 minutes I start getting errors as follows:

"There is no context for HTML-based functions. A previous function may not have used "Mode=HTML" or downloaded only non-HTML page(s), or the context has been reset (e.g., due to a GUI-based function)"

I do not get this error if I run this to completion. I have included think time in my script so therefore do not think it is a problem with my script.

Any advice here would be grateful.

Thanks