itw-javantx-*.log report class now found issue very often

Hi,

I am using icetea-web to launch the JNLP application. With icetea-web , its generated many logs, in that itw-javantx-*.log
keep reporting class not found issue very often. And the log file up with below kind on class not found error.

java.lang.ClassNotFoundException: com.ibm.nettrader.sd.ep.properties.NettraderFXMM
at net.sourceforge.jnlp.runtime.JNLPClassLoader.loadClassExt(JNLPClassLoader.java:1802)
at net.sourceforge.jnlp.runtime.JNLPClassLoader.loadClass(JNLPClassLoader.java:1602)

could see jar are added below permission;

Permission added: ("java.io.FilePermission" "C:\Users\VeenaVeeranna\.cache\icedtea-web\cache\57\....\jna-platform-4.4.0.jar" "read")

But from application side, there is not impact so such logs in the application. Why we get this errors ? how to avoid this ?