That's coming from Outlook. When the mailto: protocol is invoked, Windows looks at the registry entry HKEY_CLASSES_ROOT\mailto\shell\open\command for the command-line. On my computer it is
The %1 is where the text after the mailto: goes. If you plug in a regular e-mail address in the format of
user@host.com, it works fine. Things start to get screwy when you try put in double quotation marks. Usually this happens when people want to populate the subject field:
The " in terminates the command-line argument prematurely, causing the Windows to interpret what follows as additional commands to Outlook. Hence an invalid arguments error.
The rub is that there is no way to escape the quotation marks. All you can do is remove them. The Windows command-line shell is also not Unicode-aware. Any non-Ascii character will end up as question marks.
Anyway, in you case, the problem is that the textbox is setting the variable to HTML. Instead of mailto:user@host.com, what you're sending to getUrl() is actually mailto:<p align="left">user@host.com</p>. The quotation marks in the tag in turn is causing Outlook to barf. To fix it, give the textbox an instance name and get the text through _parent.[instance].text or _root.[instance] or something like that, depending on where the text field is.