InfoPath 2007 and InfoPath Forms Services error about user name cannot be verified

Just today an old existing SharePoint 2007 environment was re-introduced into the InfoPath development process for my current client and this morning when trying to preview a form either through InfoPath 2007 designer or InfoPath Form Services and using the InfoPath function "UserName()" the below error was given (error when viewing through InfoPath 2007).
The full error message is

InfoPathYour user name cannot be verified because the form's security settings do not permit it.Error occurred during a call to property or method 'get-UserName'.

The problem started to happen when the "Domain" textbox on the "Preview" screen and "Enter the URL of a server that is running InfoPath Forms Services and can be used to verify compatibility" textbox on the "Compatibility" screen from the "Form Options" menu was set to point to the development SharePoint server. Below are visuals of the options that I'm talking about.

The error sort of took me back at first because there weren't any problems with any of the previous forms. Since this was a new form I was thinking that there was a setting that was not correct but that wasn't the case. While troubleshooting the issue I changed the form security to "Full Trust" from "Domain" and everything was working but I knew that wasn't the solution but it got me thinking in a different direction. It got me thinking that it wasn't an InfoPath problem after all. To further that theory I changed "Preview" and "Compatibility" values to point to production and when I previewed the form everything worked with no errors. This confirmed my theory in my mind that it wasn't an InfoPath problem and I started to think what else is tied into InfoPath.

So naturally I thought it could be an IE issue because we all know that IE is an integral part of InfoPath. The first thing that I did was open each SharePoint site that I was using in IE and looked at the security zone for each site. To my surprise there was a difference between them. The production site had "Local Intranet" and the development site had "Internet". You can easily tell this by looking at the bottom right corner of the IE 7 browser. After noticing this I added the development site to the "Local Intranet" zone and then tested my InfoPath form out again and there were no errors this time.

Cheers......!

Source:www.sharepointblogs.com

Information about the characters that you cannot use in sites, folders, and files in SharePoint Portal Server 2003 or in SharePoint Server 2007

This article lists the characters that you cannot use in Microsoft Office SharePoint Portal Server 2003 site names, folder names, server names, and file names or in Microsoft Office SharePoint Server 2007 site names, folder names, server names, and file names.

Site names, subsite names, or site group names
You cannot use the following characters anywhere in a site name, in a subsite name, or in a site or Active Directory group name:
• tilde (~)
• number sign (#)
• percent (%)
• ampersand (&)
• asterisk (*)
• braces ({ })
• backslash (\)
• colon (:)
• angle brackets (< >)
• question mark (?)
• slash (/)
• plus sign (+)
• pipe ()
• quotation mark (")
• You cannot start a site name, subsite name, or a site group name with an underscore (_) character or with the period character.
• You cannot use the period character consecutively in the middle of a site name, a subsite name, or a site group name.
• You cannot use the period character at the end of a site name, a subsite name, or a site group name.

Folder names
You cannot use the following characters anywhere in a folder name or a server name:
• tilde
• number sign
• percent
• ampersand
• asterisk
• braces
• backslash
• colon
• angle brackets
• question mark
• slash
• pipe
• quotation mark
• You cannot use the period character consecutively in the middle of a folder name.
• You cannot use the period character at the end of a folder name.
• You cannot start a folder name with the period character.

File names
You cannot use the following characters anywhere in a file name:
• tilde
• number sign
• percent
• ampersand
• asterisk
• braces
• backslash
• colon
• angle brackets
• question mark
• slash
• pipe
• quotation mark
• You cannot use the period character consecutively in the middle of a file name.
• You cannot use the period character at the end of a file name.
• You cannot start a file name with the period character.

Source : support.microsoft.com