title: "System.IO.FileNotFoundException: Could not load file or assembly" when the assembly does in fact exist
body: <p>As part of our migration from .net 1.1 to .net 3.5, we had to change out a few vender DLLs.</p>
  
  <p>One of them is giving us trouble in only 1 spot out of the 4 spots we use it at:</p>
  
  <p>The trouble spot is a windows form project that uses reflection to dynamically load some DLLs that run long running processes. One of these long running processes is an agent that relies on one of our vender DLLs</p>
  
  <p>We're getting the missing assembly exception at the point where we first enter a function that references the library. I already checked the silly things such as if we had forgotten to move a reference from the old version to the new version, but that's not the case. I also checked the bin directory of the project and the assembly is there.</p>
  
  <p>Has anyone encountered a situation in which .net 2.0 runtime refuses to load an assembly like that? And if so, how could we fix the issue.</p>
  
  <p>Additional Information:</p>
  
  <p>The specific vendor in this case is dtSearch and this is the boundry where the error gets thrown:</p>
  
  <pre><code>Private Sub BuildIndex()
      SetIndexOptions()
      ExecuteIndexJob()
  End Sub
  
  Private Sub SetIndexOptions()
      'Body removed for brevity
  End Sub
  </code></pre>
  
  <p>The library is referenced in SetIndexOptions. <code>BuildIndex()</code> gets entered, but the exception happens when SetIndexOptions gets called. The function is never actually entered.</p>