Can anyone tell me why the following is giving me an 'Input string was not in a correct format.' error? 

LinkClick.aspx?fileticket=IZ/S6hKmx/Music Blip 1.WAV

I have even tried removing the slashes and spaces.  I would expect this to give me a 404 error, but instead it returned the Input string error again.

In my research I have found some other people with similar problems, but no resolution.  Any help would be appreciated.

Mitch, thank you for your reply.  I am not sure how that URL is being mangled.  Here is the code we use to build it:

public string FormatURL(object link, bool trackclicks)
{
     string linkstr = (string)link;
     return DotNetNuke.Common.Globals.LinkClick(linkstr, TabId, ModuleId, trackclicks);
}

Where link is a URL originally created with the DNN URLControl. We do not fiddle with the string at all:

NodeInfo.URL = UrlControl.Url;

Which is then saved directly to the database.  Again, thank you for your help!