Issues on powershell version 1.0

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PowerShell

Hi Guys,
PowerShell script executed with PowerShell version 2.0 and onwards gets executed successfully. But the same script when ran on powershell version 1.0 (on other system having powershell version 1.0) gets failed. So is there any other way to execute the same script on powershell v1.0 as well

Here is my script for exchange server backup:
#
#.SYNOPSIS
#Checks the backup timestamps for the servers
#and alerts if a database hasn't been backed up
#in the last 1 day
#
#.EXAMPLE
#.\Check-DatabaseBackups.ps1
#

#...................................
# Variables
#...................................
#$ErrorActionPreference = "SilentlyContinue"
$ErrorActionPreference = "Continue"
$WarningPreference = "SilentlyContinue"
set-executionpolicy -executionpolicy unrestricted -force
Add-PSSnapin Microsoft.Exchange.Management.Powershell.admin
New-EventLog -LogName Application -Source "abcd"
$xyz = ""
$ago = 24
$now = [DateTime]::Now
$dbs = ""

#...................................
# Script
#...................................

#Get all Mailbox and Public Folder databases

$dbs = Get-MailboxDatabase -Status
$dbs = $dbs += Get-PublicFolderDatabase -Status

#Check each database for most recent backup
foreach ($db in $dbs)
{ if ($db) {
if (!$db.LastFullBackup -and !$db.LastIncrementalBackup){[int]$ago = 25}
elseif ( $db.LastFullBackup -lt $db.LastIncrementalBackup )
{
[int]$ago = ($now - $db.LastIncrementalBackup).TotalHours
$ago = "{0:N0}" -f $ago
}
elseif ( $db.LastIncrementalBackup -lt $db.LastFullBackup )
{
[int]$ago = ($now - $db.LastFullBackup).TotalHours
$ago = "{0:N0}" -f $ago
}

#If backup time stamp older than threshold set alert flag and create object for alerting
if ($ago -gt "24")
{
[string]$VarDName = $db.name
foreach( $name in $VarDName){$xyz = $xyz + $db.name + "`r`n" }
}
}
}

if ($ago -gt "24") {Write-EventLog -Logname Application -Source "abcd" -EntryType Information -EventId 1 -Message ([string]$xyz)}

#end

What I have tried:

I tried the same script on powershell version 2.0 ,3.0 ,4.0 but all worked well. Issue only occurs for powershell version 1.0