just downloaded this stuff but i can't get through... this keep on coming...

Connect retry #99 diemen.nl.eu.undernet.org (6662)
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* Unable to resolve server


what shall i do?

your error ..... * Unable to resolve server

means either that the address you used is invalid or that your DNS is not working properly.

since the address you showed does in fact DNS for others,as shown here ....
* Dns resolved diemen.nl.eu.undernet.org to 195.121.6.196

that would seem to imply that your windows DNS is not set up correctly.

this could be a simple error in your windows tcp/ip dns settings.

since mirc has nothing to do with dns, its not a mirc setting causing it.