Have you already successfully installed the related external jar files (terajdbc4.jar) into your studio?
On which official version did you get that? More information will be preferred.
I can say so far the Teradata connections works well usually. Reading your error message I would say there is also no network problem in your configuration and the driver is also correctly loaded because the error message come directly from the database.
It is simply a authorization problem. Perhaps you should test the connection without context variables.
It is also sometimes a problem with the password field. Did you see this problem in the metadata wizard?
I currently work with the Talend release 5.1.1 and we do not have any problems with Teradata connections.
I am pretty sure it has something to do in which way you set the credentials. Do you use context variables or do you use the direct input (of course only for test purposes)?
If you have checked them with another tool, they should be ok. As I already sad, it could be a problem with different contexts. Therefore please create a new Teradata connection without using context variables and try to get it running.