Question

Msg 245, Level 16, State 1, Line 89
Conversion failed when converting the varchar value ‘There was an error creating the System.DirectoryServices assembly. ‘ to data type int.

This error is caused by the statement below:

begin try print '  - Preparing to create System.DirectoryServices assembly with UNSAFE_ACCESS permission'
    create assembly [System.DirectoryServices] from 'c:\Windows\Microsoft.NET\Framework\v2.0.50727\System.DirectoryServices.dll'
    with permission_set = unsafe
    print '  - System.DirectoryServices assembly created'
end try
begin catch
    print 'There was an error creating the System.DirectoryServices assembly. '+Error_number()+Error_Severity()
end catch

Answer 1

This is coming from your concatenation of number to string in the catch block. This is not allowed without casting as it tries to convert the string to number rather than vice versa and as your string literal is not numeric this attempt is doomed to fail!

You can use RAISERROR with severity 0 to print the message with the values substituted in or the alternative is to concatenate the string yourself using explicit casts.

begin catch
declare @num int = Error_number()
declare @sev int = Error_Severity()
raiserror('There was an error creating the System.DirectoryServices assembly. %d %d ',0,1, @num,@sev)
end catch