>>>>Your app. needs to be able to find this DLL. I usually add the DLL to the project (not as a reference, just to the project) then select it and set "Copy to Output Directory" to "Copy always".
>>>
>>>Do you know how should I figure out the problems? I've been debugging the test. When I come up to the Invoke1 line I saw a call to Request.Dispose method (request is a separate class that implements IDisposable interface) and then the test ended. So, I assume that this call somehow interrupted the whole thing.
>>
>>If Request.Dispose() fired unexpectedly then it's a sure sign that your code threw an uncaught exception - which was probably the failure to load the DLL.
>>You should add your own try/catch block.
>
>Here is my current code:
>
>

>  internal String RestoreData(String columnValue, String convertCode)
>        {   
>            String result = "";
>            String invoke = "gethash".MakeTag("func") + (convertCode + this.nClientNumber.ToString() + "SELECT version FROM metadata").MakeTag("data");
>            String translate = "";
>            try
>            {
>                translate = Invoke1(invoke);
>                if (translate.Left(4) == "OK :")
>                {
>                    invoke = "decryptdata".MakeTag("func") + columnValue.MakeTag("data") + translate.Substring(4).MakeTag("key");
>                    result = Invoke1(invoke);
>                }
>            }
>            catch
>            {
>                Logging.Log(1, "Using ww_local.dll generated an exception...");
>            }
>            return result;
>        }

>
>As you see, I have try/catch here. But it's getting by-passed and I see a call of Dispose method of the Request class.

http://msdn.microsoft.com/en-us/library/dd638517.aspx