What he said.

You will always get a success status (so long as the file exists).

To check for the existance of a section, use "ReadProfileString" with a null section name to get all the sections, then check if your section is present.

Something like this should do:
Code:
$NL=Chr(10)
$sSection="WFClient"
If InStr($NL+ReadProfileString("MyIniFile.ini","",""),$NL+$sSection+$NL)
   "Section '"+$sSection+"' exists in ini file" ?
Else
   "Section '"+$sSection+"' does not exist in ini file" ?
EndIf