Subject Firebird 1.5.6 not work with locla protocol

I install Firebird 1.5.6 with administrator rights, WIn 10, x64,  but i have a problem

I can not use local protocol on my PC!

All my firebird's application connect with FDB database, only i use run as administrator for my app...without Run as admin...a received

Unknown username or password

Unavailable database

BUT....if a replace local protocol with COMPNAME:<fdbfile>, if a use TCP my apps work with normal rights + Run as admin...TCP protocol works well

Where is the problem??