title: CAML Query with Contains and Or Clause Issue
body: <p>What I want to achieve : Take a keyword array as input and query Sharepoint List to return all rows which contain the keywords in the list.</p>
  
  <p>I have built a simple CAML query to query my list with one keyword (pdf) . </p>
  
  <pre><code>&lt;Query&gt;&lt;Where&gt;&lt;Contains&gt;&lt;FieldRef Name='Keyword'/&gt;&lt;Value Type='Text'&gt;pdf&lt;/Value&gt;&lt;/Contains&gt;&lt;/Where&gt;&lt;/Query&gt;
  </code></pre>
  
  <p>This works fine.</p>
  
  <p>But, when I try to use Or clause in the CAML query(see below), I get the following error</p>
  
  <p>"One or more field types are not installed properly. Go to the list settings page to delete these fields."</p>
  
  <pre><code>&lt;Query&gt;&lt;Where&gt;&lt;Or&gt;&lt;Contains&gt;&lt;FieldRef Name='Keyword'/&gt;&lt;Value Type='Text'&gt;pdf&lt;/Value&gt;&lt;/Contains&gt;&lt;/Or&gt;&lt;/Where&gt;&lt;/Query&gt;
  </code></pre>
  
  <p>I googled for the syntax and everything looks good. Please let me know what is missing.</p>
  
  <p>Thanks in advance. </p>