Cannot serialize session attribute

[Ramon Misho]

Hello iBatis people:

I am using Eclipse Version: 3.0.0 and Tomcat 5.0.19.

I edit a java file (in the Eclipse), and click on the 'Save' button. The 
'Reloading" starts as expected.   However, very often (but not all the time), I 
get the following error messages although they have no impact on the compiling 
process.  

                Cannot serialize session attribute myfileBean for session 
<some_id_with_letters_and_number>
                ..................etc
                
The 'myfileBean' is the name of one of my JAVA files.   The strange thing is 
that when this error is generated, I am usually working with another JAVA file.

Any ideas?

Thanks.
Ramon