ftphost.dll missing / not found error: unavoidably pc may get infected by virus like trojandownloader:win32/agent.lf or controlled by malware like fixbyweb. after they are removed by antivirus such as avast internet security, the infected file ftphost.dll would be deleted as well so that missing problem is found.

This is all lower case. Can you fix that?
ftphost.dll missing / not found error: Unavoidably PC may get infected by virus like TrojanDownloader:Win32/Agent.LF or controlled by malware like FixByWeb. After they are removed by antivirus such as Avast Internet Security, the infected file ftphost.dll would be deleted as well so that missing problem is found.