tomcat 5.5.16 and CompressionFilter + EncodingFilter class not found

During the startup of apache-tomcat-5.5.16 i receive the
following errors
in localhost.2006-03-30.log

Mar 30, 2006 4:12:11 PM
org.apache.catalina.core.StandardContext
filterStart
SEVERE: Exception starting filter Compression Filter
java.lang.ClassNotFoundException:
compressionFilters.CompressionFilter


Mar 30, 2006 4:12:11 PM
org.apache.catalina.core.StandardContext
filterStart
SEVERE: Exception starting filter Set Character Encoding
java.lang.ClassNotFoundException:
filters.SetCharacterEncodingFilter

Can anybody help me to understand what is wrong?
Thanks.
Maurizio Salviato
Servizio Supporto Sistemi
Integrazione Sistemi & Office Automation Gruppo PAM
s.p.a.
(041-5496-226 fax.041-5496-296
* maurizio_salviatogruppopam.it


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