This might seem obvious but your execution policy is set to remotesigned? Also you may want to just run Write-SmoToCsvFile.ps1 and pass in the server name instead of using Run-SmoToCsvFile.ps1 as a test:

C:\WINDOWS\system32\WindowsPowerShell\v1.0\powershell.EXE -command "C:\SQLPSX\Write-SmoToCsvFile.ps1 'MyServer'"