why my fckeditor with bring upload img on iis restart?

hi
i encountered a problem, bring upload img on iis restart, why?
i use vs2003 , fck dll version is 2.2
and this my web.config section:

<add key="FCKeditor:BasePath" value="~/"/>
<add key="FCKeditor:UserFilesPath" value="/Files/" />

o,i m a chinese coder, foreign language is bad, i will use code talk you my opera flow, please help me,thanks!
my flow:

with upload image opera
{
if ( " i choice "Browse Server" button " )
{
all's ok ,no problem. file save to "/Files/Image/".
}
if( " i choice "Upload" Tab " && click "Send it to the Server" )
{
file save to "/Files/", and my iis restart, my cookie and session overtime
}
}

emm...its whether clear ? please forgive me , thanks!