Resolution:
If the DISPLAY and LD_LIBRARY_PATH variables are set correctly, the user may not be having the write permission to the designer log directory. The solution is to give  write permission to the log directory. By default, Log directory and user preference file on Unix machine are  saved under "$HOME/.TIBCO",  which has custom_palettes, Designer.prefs, and logs directories/files. It is also safe to delete "$HOME/.TIBCO" directory, because it will be automatically recreated the next time the user uses Designer.