Hello, I'm trying to configure RadASM to use Fasm compiler. I did get last RadASM version: 2.2.2.0, the full package, where fasm.ini is already configured and I did decompress fasm1.68 package in "c:\fasm". When I compile "TestFasm.Asm" from RadASM projects, produces an error: "enter - invalid operand" in line 19 of "TestFasm.Asm".

Can anybody help me, please?

it seems that there's an error in your source file (on line 19) and RadAsm has nothing to do with it. Try to assemble TestFasm.Asm from command line (c:\fasm\fasm.exe TestFasm.Asm)

The result is as follows:

c:\fasm\fasm TestFasm.Asm
flat assembler version 1.68 (1513071 kilobytes memory)
TestFasm.Asm [6]:
include '%fasminc%\win32a.inc'
error: file not found.

There's an error in ERROR instruction.
If you look at Intel 64 and IA-32 Architectures Software Developer's Manual, Volume 2A, (http://www.intel.com/Assets/PDF/manual/253666.pdf), pg. 3-325, you'll see, that enter instruction should be issued with some parameters:

enter imm16,0
enter imm16,1
enter imm16,imm16

Maybe there's some missing macro which defines enter and return commands.

avcaballero, you should add a %fasminc% environment variable (%fasminc%=<path_to_fasm>\INCLUDE)