Hello Lyd2,
What are you trying to install the Citrix Client on?
http://www.citrix.com/English/ss/downloads/details.asp?downloadId=1681207
These plugin support Windows 2000, XP, Vista, 2003, & 2008
There is a newer client that looks like it is for Windows 7. Receiver for Windows (Online Plug-in 12.1) Release Date: 10/28/2010
Use Receiver for Windows “(Online plug-in – web)” to access hosted applications from your Citrix Web Interface.
http://www.citrix.com/English/ss/downloads/details.asp?downloadId=2304987&productId=186&c1=sot2755
This Receiver can be used with Windows 7, XP, Vista, 2003, 2008, & 2008R2.
However, it would be best to talk to Citrix to be sure you are getting the correct client download.
Hope this helps.
Marilyn