You may want to try out both and therefore you selected both, and specified the same IDE path for both SDE and DB-VA, and then you received a strange error message.
This error message is complaining you try to install both SDE and DB-VA on the same IDE. Both SDE and DB-VA works by integrate with the IDE. You can either installing one, but not both on the same IDE. Installing both on the same IDE will cause conflict thus both of them will not work, and that’s why you got the error message.
In fact, DB-VA is a subset of SDE. The SDE Enterprise Edition covers all features of DB-VA. So if you are installing the software for evaluation purpose, you can simply install SDE. We took SDE for Eclipse as an example and the following link showing DB-VA is part of SDE.
And if you really want to install both of them to try out, then you need to prepare 2 IDEs, one for SDE and one for DB-VA.