Strange 404 errors. Is it a virus or have I been hacked

I have been getting some string 404 messages on my site. I am baffled as to why they are occurring. Any insight on why and how to resolve them would help me greatly thanks.

Specs: IIS7 App pool 4.0 Integrated

Some Errors:
CLqytfCzkbMCFRSSPAodxlEAeg
CIumpruzkbMCFeN4cAodB2EAoA
CI-R8Le2kbMCFcFU4god5WgAjg
404;http://xxxxxx.com:80/cache/b04d1b258a3ac0ae471f537603e6172a

80/crossdomain.xml
apple-touch-icon-precomposed.png (There is NO Png like this on my site)
http://xxxxxx.com:80/index.jsp (NO index.jsp on my site)