If someone wrote a PowerShell program, with multiple lines and without caring the coding standard and you got stuck to find where the error is, so very simplest way which I am thinking is just use below piece of code which saves your time and let you know about a line which is having an issue.

InvocationInfo can provide information about how and where this command was invoked

So just use simple try-catch like below

try {
    #<replace with your code>
}
catch {
    $_ |select -expandproperty invocationinfo
    write-host "$($_.Exception.Message)" -foregroundcolor red  
    break;
}