The first time I log into Gemini aftern not using it for several days, if I try to batch edit some issues, it works just fine.  If, however, I have done anything in Gemini recently, like adding isues or creating users or whatever, when I hit the "Batch Edit" link, I get the following error message.  Does this ring a bell for anyone?  Thanks.
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Server Error in '/Gemini' Application.

        <h2> <i>Specified cast is not valid.</i> </h2></span>

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        <b> Description: </b>An

unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.

        <b> Exception Details: </b>System.InvalidCastException: Specified cast is not valid.<br><br>

        <b>Source Error:</b> <br><br>

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An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below.

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        <b>Stack Trace:</b> <br><br>

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                  <code></code><pre>[InvalidCastException: Specified cast is not valid.]<br>   Gemini.SessionBag.GetIssuesFilter() +1566<br>   Gemini.BatchUpdate.GetFilteredIssues() +357<br>   Gemini.BatchUpdate.Page_Load(Object sender, EventArgs e) +4439<br>   System.Web.UI.Control.OnLoad(EventArgs e) +67<br>   Gemini.BasePage.OnLoad(EventArgs e) +4<br>   System.Web.UI.Control.LoadRecursive() +35<br>   System.Web.UI.Page.ProcessRequestMain() +750<br></pre></td></tr></tbody></table></font><br>