Export-Clixml : The given path's format is not supported.

I am currently trying to export to xml and my script looks like this

$xml = $reportBuilder.GetMyReport()

$fileDestination = $filepath + "\" + $fileName + ".xml"

$xml | Export-Clixml -Path $fileDestination

when I debug this code, $fileDestiniation hold the value c:\folder\filename.xml

However, I keep getting the error that states "Export-Clixml : The given path's format is not supported". At this point am lost of ideas, cause I do not know why its saying that. Especially since the value for $fileDestination is a valid one. Please help.