How is it possible that 64-bit process can load dll written in .net 1.1 although there is no 64-bit compiler for framework 1.1?
I have old .net 1.1 dll, I've created simple 64-bit console application (.net 4.0) which refers this library and calls a function, and everything works fine.
You can load a .NET 1.1 assembly into later versions of the CLR. You haven't said what framework your 64-bit console app is targeting, but basically it'll be loading your 1.1 assembly into the 2.0 or 4.0 CLR with no problems.
You would have had problems (I think) if it had been a mixed-mode assembly with 32-bit code in, but a plain IL-only assembly should be fine.