PowerShell: Cannot find an overload for IndexOf and the argument count: 2 - powershell-remoting

Question

I am attempting to use a portion of a script I wrote to return a list of Local Groups a specified user may be part of on a remote server so they can be quickly removed from said Local Group. Everything seems to work fine until the groups a person may be part of goes below two. When there is only one group I get the following error:
Cannot find an overload for "IndexOf" and the argument count: "2".
At line:177 char:30
+ [string]([array]::IndexOf <<<< ($localGroups, $_)+1) + ". " + $_
+ CategoryInfo : NotSpecified: (:) [], MethodException
+ FullyQualifiedErrorId : MethodCountCouldNotFindBest
Here are the Functions I wrote for this particular script...
This function will return a list of groups the given user is part of:
function Get-LocalGroupAccess
{
[CmdletBinding()]
Param(
[Parameter(Mandatory=$true)]
[string]$fqdn,
[Parameter(Mandatory=$true)]
[string]$userName
)
Process
{
$serverPath = [ADSI]"WinNT://$fqdn,computer"
$serverPath.PSBase.Children | where {$_.PSBase.SchemaClassName -eq 'group'} | foreach {
$lGroup = [ADSI]$_.PSBase.Path
$lGroup.PSBase.Invoke("Members") | foreach {
$lMember = $_.GetType().InvokeMember("Name", 'GetProperty', $null, $_, $null).Replace("WinNT://","")
if ($lMember -like "$userName")
{
$localAccess += #($lGroup.Name)
}
}
}
return($localAccess)
}
}
This function sets the User Object (I am not sure this is the technical term):
function Set-UserObj($userDomain, $userName)
{
$userObj = [ADSI]"WinNT://$userDomain/$userName"
return ($userObj)
}
This function set the FQDN (checks to see if it is pingable):
function Set-FQDN($fqdn)
{
do{
$fqdn = Read-Host "Enter the FQDN"
} while (-not(Test-Connection $fqdn -quiet))
return($fqdn)
}
This function will take the selection for the group you want to remove the given user from, change it to the proper place in the array, and return the group:
function Set-LocalGroup($localGroups, $selectGroup)
{
$selectGroup = Read-Host "What group would you like to add $userDomain/$userName to?"
$selectGroup = [int]$selectGroup -= 1
$setGroup = $localGroups[$selectGroup]
return($setGroup)
}
This function sets the Group object (not sure if this is the technical term):
function Set-GroupObj($fqdn, $group)
{
$groupObj = [ADSI]"WinNT://$fqdn/$group"
return($groupObj)
}
This function removes the given user from the group selected:
function Remove-UserAccess ($gObj, $uObj)
{
$gObj.PSBase.Invoke("Remove",$uObj.PSBase.Path)
}
In the script the user name, domain and FQDN are requested. After these are provided the script will return a list of groups the given user is part of. Everything works fine until the user is part of one group. Once that takes place, it throws the error I pasted above.
Please note, this is my first time posting and I am not sure what information is needed here. I hope I provided the proper and correct information. if not, please let me know if there is something else that you require.
Thanks!

Answer 1

I went back and was looking at the difference, if there were any, in the variable $localGroups that I was creating (I used Get-Member -InputObject $localGroups). I noticed that when $localGroups had only one item it was a System.String type but when it had more than one item in it, it was a System.Object[] type. I decided to do the following and it addressed the issue I was having:
$localGroups = #(Get-LocalGroupAccess $fqdn $userName)
previous code:
$localGroups = Get-LocalGroupAccess $fqdn $userName
Everything is working as it should because I forced the variable to a static type instead of allowing it to create whatever type it wanted.