You also need Borland's assembler, TASM, which did not come with the compiler.
Frankly, though, you are using antique software (it says so on Embarcadero's download page) designed for 16-bit XT systems. Unless you are writing new software for a museum computer, you should immediately forget BCC 5.5 and download a modern compiler.
You can get Microsoft's latest C++ compiler (MSVC Community Edition) which supports inline assembly on x86: https://www.google.com/search?q=msvc+community+2017
Don't forget to select the following components during installation:
• Visual Studio C++ core features
• Windows Universal C Runtime
I think you can also do inline assembly with MinGW.
Finally, you have probably got an XY problem. It is unlikely you should have any need to mix assembly into your C or C++, even if you are writing a device driver. Perhaps a better description of your actual problem statement and we can give you useful advice.