I have found the problem! The problem is during connection to the database.

I wrote:
Qt Code: 
  1. QSqlDatabase database; 
  2. database.setDatabaseName("D:\Test\d1.fdb");
  3. database.setConnectOptions(user id=SYSDBA;password=masterkey;server type=Embedded;auto_commit=True;auto_commit_level=4096;connection lifetime=1; DataBase="D:\Test\d1.fdb");
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But should be:
Qt Code: 
  1. QSqlDatabase database; 
  2. database.setDatabaseName("D:\Test\d1.fdb");
  3. database.setUserName("SYSDBA");
  4. database.setPassword("masterkey");
  5. database.setConnectOptions(server type=Embedded;auto_commit=True;auto_commit_level=4096;connection lifetime=1; DataBase="D:\Test\d1.fdb");
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So, we should set User name and Password using methods "setUserName", "setPassword". That is why I did not have permissions to execute procedures.