Before the first try insert a write-host like this to find where the problem occurs.
write-host "<<<DEBUG1>>>"
Add-PSSnapin VeeamPSSnapIn -ErrorAction SilentlyContinue
write-host "<<<DEBUG2>>>"
try
{
$tapeJobs = Get-VBRTapeJob
write-host "<<<veeam_tapejobs:sep(124)>>>"
write-host "JobName|JobID|LastResult|LastState"
foreach ($tapeJob in $tapeJobs)
If the try fails or the load at the beginning then you should see a minimum of one line.