If by European activation code you mean it is from Codemasters, Nakiami is correct. Codemasters no longer runs LOTRO in the EU and their codes are no longer valid. If that is what you have, you should let the seller know the product is, basically, expired and not usable.
Until June 2011, the European servers of LOTRO used to be maintained by Codemasters, not Turbine. After Turbine took over the EU servers, all product keys etc for LOTRO that were issued by Codemasters - for example in retail boxes, etc - were no longer accepted by Turbine. All the existing EU players had to undergo a (data) transfer to the new EU servers now managed by Turbine. That's why if you look at join date on the forums, a lot have June 2011 as their join date, such as mine - even for people who joined when game launched in 2007.
Thus it has been over a year now since any ex-Codemasters product has been valid for the game. If you bought the product from a retailer, then there should be a law in your country (hopefully) that gives you protection and means you can ask for your money back. In the UK, the Sale of Goods Act might apply for example or the Trade Descriptions Act. If you bought it from ebay using paypal, then put in a charge back claim if the seller won't refund, as really a seller should have been aware of this.
Until June 2011, the European servers of LOTRO used to be maintained by Codemasters, not Turbine.
After Turbine took over the EU servers, all product keys etc for LOTRO that were issued by Codemasters - for example in retail boxes, etc - were no longer accepted by Turbine.
This statement is not correct. Turbine never accepted Codemasters keys. Codemasters never accepted Turbine keys. For several years there was some customer frustration by people buying a key. Taking that key and trying to use to to create or extend an account.
At the end of May, 2011 Codemasters shut down. The Codemasters keys became worthless. I suppose there are some Japanese and Korean keys knocking around that are also worthless since those game operators shut down.
It has been this way all along. You had to make sure to get the right key - Chinese, EU (Codemasters), Japanese, North American (Turbine), Korean or Russian for the game operator that you wanted to provide the service.
Unless stated otherwise, all content in this post is My Personal Opinion.
so where can i found a new european activation code???? and what webpage can i use it?
There is no european activation code. You don't need it in order to play. You can download the client from this website, and it contains Moria and ALL the code you will ever need.
IF you can find a US version of Mines of Moria, you can use its code on your account... but you can buy Mines of Moria with Turbine Points after you start playing. You don't need any kind of activation code EVER... though some types of purchases you MAY make will require them, it's not the primary way to get content in this game.