Trouble with Powershell functions in .ps1

I'm trying to modify a working script, to make it modular. The purpose of the script is to connect to a DPM server, get the attached libraries, and inventory them. Once the inventory is done, the script marks the appropriate tapes as 'free'. The script is below

I have two problems. The first one has come and gone, as I've edited the script. When I run the script: .\script.ps1, Powershell says:

C:\it\test.ps1 : Cannot validate argument on parameter 'DPMLibrary'. The argument is null. Supply a non-null argument and try the command again.

At line:1 char:11 + .\test.ps1 <<<<

CategoryInfo : NotSpecified: (:) [Write-Error], WriteErrorException FullyQualifiedErrorId : Microsoft.PowerShell.Commands.WriteErrorException,test.ps1

The second problem comes when I've just copied the functions into the shell. The Get-Libraries function works fine and returns the properties of the connected library. When I pass the parameter to Inventory-DPMLibrary, the inventory completes. When I pass the library parameter into the Update-TapeStatus function, I get an error that says

Bad argument to operator '-notmatch': parsing "slot" - Quantifier {x,y} follo wing nothing..

At line:6 char:77

$tapes = Get-DPMTape -DPMLibrary $lib | Where {$_.Location -notmatch <<<< " *slot *"} | Sort Location

CategoryInfo : InvalidOperation: (:) [], RuntimeException ? + FullyQualifiedErrorId : BadOperatorArgument

It looks like the $liblist parameter is null, even though the variable isn't. What gives?

Here is the script:

[CmdletBinding()]
param(
    [ValidateSet("Fast","Full")]
    [string]$InventoryType = 'Fast',

    [string]$DPMServerName = 'server1'
)

Function Import-DPMModule {
    Try {
        Import-Module DataProtectionManager -ErrorAction Stop
    }
    Catch [System.IO.FileNotFoundException] {
        Throw ("The DPM Powershell module is not installed or is not importable. The specific error message is: {0}" -f $_.Exception.Message)
    }
    Catch {
        Throw ("Unknown error importing DPM powershell module. The specific error message is: {0}" -f $_.Exception.Message)
    }
}

Function Get-Libraries {
    Write-Verbose ("Getting list of libraries connected to {0}." -f $DPMServerName)
    Try { 
       $libraries = Get-DPMLibrary $DPMServerName -ErrorAction Stop | Where {$_.IsOffline -eq $False}
    }
    Catch [Microsoft.Internal.EnterpriseStorage.Dls.Utils.DlsException] {
        Write-Error ("Cannot connect to the DPM library. It appears that the servername is not valid. The specific error message is: {0}" -f $_.Exception.Message)
        Return
    }
    Catch {
        Write-Error ("Unknown error getting library. The specific error message is: {0}" -f $_.Exception.Message)
        Return
    }

    Return $libraries
}

Function Inventory-DPMLibraries ($liblist) {
    Foreach ($lib in $liblist) {
        If ($InventoryType -eq "Fast") {
            Write-Verbose ("Starting fast inventory on {0}" -f $lib)
            $inventoryStatus = Start-DPMLibraryInventory -DPMLibrary $lib -FastInventory -ErrorAction SilentlyContinue
        }
        Else {
            Write-Verbose ("Starting detailed inventory on {0}" -f $lib)
            $inventoryStatus = Start-DPMLibraryInventory -DPMLibrary $lib -DetailedInventory -ErrorAction SilentlyContinue
        }

        While ($inventoryStatus.HasCompleted -eq $False) {
            Write-Output ("Running {0} inventory on library: {1}" -f $InventoryType.ToLower(),$lib.UserFriendlyName)
            Start-Sleep 5
        }
        If ($inventoryStatus.Status -ne "Succeeded") {
            Throw ("Unknown error in inventory process. The specific error message is: {0}" -f $_.Exception.Message)
            Return
        }
    }
}

Function Update-TapeStatus ($liblist) {
    Foreach ($lib in $liblist) {
    write-host ("in tapestatus. the lib is: {0}" -f $lib)
        Write-Verbose ("Beginning the process to determine which tapes to mark 'free' on {0}" -f $lib)
        Write-Verbose ("Getting list of tapes in {0}." -f $lib)
        $tapes = Get-DPMTape -DPMLibrary $lib | Where {$_.Location -notmatch "*slot*"} | Sort Location

        Foreach ($tape in $tapes) {
            If ($tape.DisplayString -eq "Suspect") {
                Write-Verbose ("Remove suspect tapes from the DPM database.")
                Invoke-Command -ScriptBlock {osql -E -S server2 -d DPMDB_server1 -Q "UPDATE tbl_MM_ArchiveMedia SET IsSuspect = 0"} -whatif
                Start-DPMLibraryInventory -DPMLibrary $lib -FastInventory -Tape $tape -whatif
            }
            #Run a full inventory on "unknown" tapes
            #Make recyclable tapes "free"
            If (($tape.DisplayString -notlike "Free*" -and $tape.DataSetState -eq "Recyclable") -or ($tape.DisplayString -like "Unrecognized")) {
                Write-Output ("Marking the tape in slot {0} as free." -f $tape.Location)
                Set-DPMTape $tape -Free -whatif
            }
            If ($tape.OMIDState -eq "Unknown") {
                Write-Warning ("Unknown tape found in slot {0}. Beginning detailed inventory." -f $tape.location)
                $inventoryStatus = Start-DPMLibraryInventory -DPMLibrary $lib -DetailedInventory -Tape $tape -whatif
                While ($inventoryStatus.HasCompleted -eq $False) {Write-Output ("Running full inventory on the tape in slot {0} (label {1})" -f $tape.Location,$tape.Label); Start-Sleep 10}
            }
        }
    }
}

#Calling functions
Try {
    Import-DPMModule
}
Catch {
    Write-Error $_
    Exit
}

Try {
    $liblist = Get-Libraries
}
Catch {
    Write-Error $_
    Exit
}

Try {
    Inventory-DPMLibraries
}
Catch {
    Write-Error $_
    Exit
}

Update-TapeStatus $liblist

Thanks.

Solution

Your function Inventory-DPMLibraries expects a parameter ($liblist):

Function Inventory-DPMLibraries ($liblist) {
  ...
}

However, you don't supply that parameter when you call the function:

Try {
  Inventory-DPMLibraries
}
Catch {
  Write-Error $_
  Exit
}

Change the above into this:

Try {
  Inventory-DPMLibraries $liblist
}
Catch {
  Write-Error $_
  Exit
}