how can I prevent this from causing an error?

[stanav]

I understand that which is why i'm here asking for help.

form1.webbrowser1.navigate("www.yahoo.com")

'What code do I put here to wait for form1.webbrowser1 to finish navigating?

'after navigation fill out the yahoo search box

You need to stop thinking in linear way... Re-read post#11... No need for a busy waiting loop. In the documentcompleted event handler, you just make sure that the document is really completed, then check which url it just finised loading... And then go on to the next task right from within the documentcompleted event handler. That means you can raise an event back to form4 to let it knows that the page has done loading if you want to...