Tim,

Which version of .Net are you using - 1.0 or 1.1?  I've had other
problems w/ JScript.Net in 1.0 that were fixed in 1.1.

Are the C# catch blocks in the correct order?  I.e.:

 try
   ...
 catch (Microsoft.JScript.JScriptException jse)
   ...
 catch (Exception ex)
   ...

For some reason it's hard to find more info on JScriptException.  The
.Net help file is mute on the subject, and MSDN is hardly better.  
You might try searching Google and MSDN for "JScriptException" to see
if those entries help.

Looking at the source code for the JScript.Net compiler (in the SSCLI
distribution), I found this in jscriptexception.cs:

 //-----------------------------------------------------------------
--------------------------------------
 // JScriptException
 //
 //  An error in JScript goes to a COM+ host/program in the form of
a JScriptException. However a
 //  JScriptException is not always thrown. In fact a
JScriptException is also a IVsaError and thus it can be
 //  passed to the host through IVsaSite.OnCompilerError(IVsaError
error).
 //  When a JScriptException is not a wrapper for some other object
(usually either a COM+ exception or
 //  any value thrown in a JScript throw statement) it takes a
JSError value.
 //  The JSError enum is defined in JSError.cs. When introducing a
new type of error perform
 //  the following four steps:
 //  1- Add the error in the JSError enum (JSError.cs)
 //  2- Update GetErrorType() to return a value from the ErrorType
enum (in ErrorConstructor) for the
 //     error you just defined. GetErrorType() is a map form JSError
to a JScript object in the Error
 //     hierarchy
 //  3- Update Microsoft.JScript.txt with the US English error
message
 //  4- Update Severity.
 //-----------------------------------------------------------------
--------------------------------------

And - from the same jscriptexception.cs file - the class signature
for JScriptException is:

[Serializable] public class JScriptException : ApplicationException,
IVsaError

Hope this helps.

Chris.
-------------
C.R. Timmons Consulting, Inc.
http://www.crtimmonsinc.com/