I think you definitely need to give it a test with 2nd OPC client. If you get the same error, then contact the OPC Server vendor (CoDeSys) and try to resolve with them. Only if other OPC clients work but the one you intend does not, then look further for the cause on the OPC client side.
Simple test clients can be obtained over the Web for free, and are included in packages form vendors such as Software Toolbox, Matrikon, ICONICS etc.

not tried, in fact we only work with this opc, and other machines are working perfectly since uninstalled and installed again opc, but it still fails!

This looks like a problem on the OPC server side. Have you tried any other OPC client?

hello, I'm trying to connect to server opc: CODESYS.OPC.02, the text of the error message is exactly what I wrote up there, nothing else, the text is as follows: OPC operation failed - can not supply ClassFactory request class, the error itself, only happens when trying to communicate the software demo, however, can not communicate, then I think the same thing is happening.
carefully Alison R. S. Haubert.

Hello,
can you provide more details please, and steps to reproduce?
Are you using QuickOPC.NET? Which OPC server are you trying to connect to? Is the error coming from your own application, or the demo application in the product? Please provide the *precise* text of the error message.
Thank you

hello, I have a problem here, opc is not communicating with my software, and when I try to get some information for software demo he accuses me the following error - OPC operation failed - can not supply ClassFactory request class - I went online and found pequisando that this problem should be related to a. dll corrupt or something, I've tried everything I know to try to resolve the problem, but without success, WILL SOMEONE eVER HAD a PROBLEM LIKE AND kNOW HOW TO sOLVE IT?
obs:I use windows xp service pack 2
I thank you for understanding.
carefully Alison R. S. Haubert.