You can't load shared Unix libraries using the
Java classpath.
You should probably be doing this at the operating system level. Googling for your library, it appears that you are attempting to use the SAP Suite Adapter for JCo. There are installation instructions
here.
I am very reluctant to add JAR files to Weblogic's classpath as it may have unintended consequences with Weblogic's dependencies, so the SAP JAR file should probably be in your WAR/EAR unless you are using Weblogic's data sources to manage/pool connections.