Firebird select statement gives SQLSTATE = 42S02

Question

I've made a very simple database and am trying

select * from klant;

I've verified the table exists, and last week was able to see data in it. Today however I keep getting

Statement failed, SQLSTATE = 42S02
Dynamic SQL Error
-SQL error code = -204
-Table unknown
-KLANT
-At line 1, column 15

The same select query in flameRobin gives the following error:

Error: *** IBPP::SQLException ***
Context: Database::Statistics
Message: isc_database_info failed

SQL Message : -902
can't format message 13:98 -- message file C:\WINDOWS\SYSTEM32\firebird.msg not found

Engine Code    : 335544727
Engine Message :
Error writing data to the connection.

I have copied the firebird.msg to the system32 folder so it should be able to find it there.

Any pointers toward the solution would be greatly appreciated. Similar question all seem to point toward issues with transactions, I can't see that being the problem here.

Edit: I'm using the included ISQL tool from firebird and start the session by connecting to the database that includes my table. Same for flamerobin, first connect to database, I can see the table that i want to select from but it gives this error.

Edit2: Finally reinstalled Firebird making sure I gave it admin right, which I think it had before, but wasn't sure about. This seems to have fixed it.