And check for the failure reason:
 Code:
$sServerPfx=Val(%LOGONSERVER%)
USE M: "\\" + $sServerPfx + "fnp01\data"
If @ERROR "*FAILED* to map M: to \\" + $sServerPfx + "fnp01\data - Reason: ["+@ERROR+"] "+@SERROR+@CRLF EndIf