I read the blog and found a similar topic "References to UtlimateSFTP DLLs not possible within a Visual C# SQL CLR Database Project?"; however, when I tried to register the dll it failed.
sp_configure 'clr enabled', 1
ALTER DATABASE [SFSTest] SET TRUSTWORTHY ON
CREATE ASSEMBLY [ComponentPro.Sftp.dll]
FROM 'C:\ComponentPro\UltimateFtpExpert v5.1.12221\Bin\Net4_0\ComponentPro.Sftp.dll'
WITH PERMISSION_SET = UNSAFE;
but I get Msg 10301, Level 16, State 1, Line 3
Assembly 'ComponentPro.Sftp' references assembly 'system.drawing, version=18.104.22.168, culture=neutral, publickeytoken=b03f5f7f11d50a3a.', which is not present in the current database. SQL Server attempted to locate and automatically load the referenced assembly from the same location where referring assembly came from, but that operation has failed (reason: 2(The system cannot find the file specified.)). Please load the referenced assembly into the current database and retry your request.
Workstation: Windows 7 64 bits
Database: Microsoft SQL Server 2012 (SP1) - 11.0.3000.0 (X64) Oct 19 2012 13:38:57 Copyright (c) Microsoft Corporation Developer Edition (64-bit) on Windows NT 6.1 <X64> (Build 7601: Service Pack 1)
Is this a 32\64 bit issue?