How to fix the 'object' does not contain a definition for error

I'm developer fall in love with C#, .NET and Mono.
Designing and programming websites since 2001.
I like literature (to read and to write), playing football (soccer)... and of course I'm great fan of La Roja (Spain football team)

At now I work in GetMeAnApartment, I do Research and Development features to upgrade our website (asp.net, MVC, MySQL) and business model (rental short stay apartments)


My Knowledge:
LANGUAGES: C#, XML, HTML, JavaScript, ActionScript, php, VisualBasic Script

TECHNOLOGIES: asp.net, asp.net mvc, php, flash, GTK#

APPLICATIONS: wordpress, wikimedia, I programmed modules for Macromedia Flash MX for myself

FRAMEWORKS: .Net Framework, Mono

SERVERS: IIS, apache2

SO: Windows, Debian

SOFTWARE: Visual Studio 2010, 2008. Monodevelop. Glade. Illustrator. Indesign. Photoshop. Dreamweaver.


Employment:

GetMeAnApartment
IT Director and website developer, 2010 - present

Círculo Rojo Publicidad y Comunicación
IT Director and websites developer, 2007 - 2010

Dédalo Creative
Co-founder,Programmer and Developer, Graphical designer 2006 - 2007

Costa Mediterránea Comunicación
Chief writer, 2004 - 2006

Stalker Creacion
Web designer and developer, 2001 - 2003

Education
Myself
Designer and Programmer, 2001 - present

Jaime I, University
Advertising, 2000 - 2005