As I don't know what exactly it is that you allege the federal government has done I don't know if there were any civil rights violations. I can tell you that simply failing to investigate an alleged crime is not a civil rights violation, however.
If the claim was a tort claim against the federal government and you named the FBI the judge would dismiss that claim because you didn't name the proper party. In a FTCA claim you have to name the United States, not the specific agency involved. That's just how the statute is drafted. The court in that instance is not telling you that you have a good claim against the government. It is simply telling you that you made a procedural mistake in the lawsuit and what you need to do to fix that particular mistake.
The FTCA does waive sovereign immunity for the federal government for many types of tort claims. Negligence claims are one type of tort claim. The problem is that the FTCA does not waive immunity for all tort claims. There are some kinds of tort claims that the FTCA excludes from the waiver of sovereign immunity, which means that you cannot sue the federal government for those particular claims. One of those, as I've mentioned, are claims of negligence in performing a discretionary act.

