Alex,components and templates are working fine..there is no issue in code....once we open the page these exceptions are comming at the background.,,this is the issue...
Once you open a livesite page, the java codes in the external components will be executed and in GUI "Loading " Message will be shown
If the code is executed successfully, the desired output of component is shown else error message will be thrown in GUI as well as in servlet_log
So check your parameters are passed correctly to the external jave code, do have a debug option enabled in your java code, if so enable it and check your code execution, then you will be able to narrow down to root cause of the error.