Excel, error using SaveAs method

I made  ascript to tlist the domain admins for a non technical person to run, to list the domain admins. That works fine. I want to put a nice touch on it though and give them an Excel file to work in. I can populate the workbook just fine, but when I save it, I get an error. there are lots of references to this error, but the most common fix doesn't work, adding the 2 directories (link to fix here: http://www.techdecode.com/wp/?p=58)

Code:

cls
import-module ActiveDirectory
$arrUsers = @()
#get list of domain admins
$return = Get-ADGroupMember -Identity "domain admins" | Sort-Object
#start excel environment
$xl = New-Object -ComObject "Excel.Application"
$xl_workbook = $xl.Workbooks.Add()
$xl_worksheet = $xl_workbook.ActiveSheet
$xl_cells = $xl_worksheet.Cells
$row = 1
$col = 1
foreach ($user in $return)
{
	$xl_cells.item($row, $col) = $user.name
	$row = $row + 1
}
$xl.visible = $true
#save document
$date = Get-Date -Format "yyyyMMdd"
$path = "c:\temp\domain_admins_$($date).xlsx"
$xl_workbook.SaveAs($path)

The error I get is:

Exception calling "SaveAs" with "1" argument(s): "SaveAs method of Workbook class failed"
At c:\test\Powershell Scripts\list domain admin group members.ps1:29 char:20
+ $xl_workbook.SaveAs <<<< ($path)
    + CategoryInfo          : NotSpecified: (:) [], MethodInvocationException
    + FullyQualifiedErrorId : ComMethodTargetInvocation