The remote host is missing an update to the system as announced in the referenced advisory.
The following package is affected: firefox
CVE-2010-1121 Unspecified vulnerability in Mozilla Firefox 3 on Windows 7 allows remote attackers to execute arbitrary code via unknown vectors that trigger memory corruption, as demonstrated by Nils during a Pwn2Own competition at CanSecWest 2010.
Solution: Update your system with the appropriate patches or software upgrades.