This error message indicates that Aware IM cannot find one of the system files (activation.jar) or the file is corrupted. Are you saying that Aware IM was working fine before?
Please check the following:
1) Show contents of Aware IM application (AwareIM.app)
2) Check that the following file exists:
AwareIM.app/Contents/Resources/java/JBoss/server/bas/lib/activation.jar
If the file is not missing it is also possible that the property file that describes java classpath is missing or corrupt. Please do the following:
1) Show contents of Aware IM application (AwareIM.app)
2) Check that the following file exists:
AwareIM.app/Contents/Info.plist
3) Double click on this file to open property editor
4) Check that the following property exists:
Root/Java/ClassPath/$APP_PACKAG