Well, the supplied files that describe your intended project are, to my surprise - in serbian...

Even the comments in the source code are in serbian, and at the first glance, device is featuring some latin-cyrillic character conversion as well...

I don't know whether you do understand serbian but I'm sure that anybody who tries to help you without knowledge of the language will have some hard time understanding the project solely on the basis of schematics/code without proper (and indeed detail) explanation from the author of design in the articles...

To all non-serbian speaking members that poke inside this project, a few notes:

Voja Antonic, author of the article, is renowned (at least in Serbia) author of many articles concerning electronic, computers and mC projects. Amongst other things he authored many introductory projects and articles for novices such as this one.

In the zip archive two pdf files are:

1) First Sherlock's Case - Oct 95.pdf
2) Moving Letters - Nov 95.pdf

Both are articles from corresponding issues of magazine 'PC Press' (serbian issue, http://www.pcpress.co.yu, mailto://pc@pcpress.co.yu) and are 'part of the bigger picture'. So, although somewhat complete, they implicitly rely on other articles of the same project...

1) Sherloch is an introductory project to the world of mCs. in short, DIY SBC development board based around 8031, supports eproms ranging from 2764 to 27512 (conf. jumper), ram, rs232...

2) Moving Letters, is project, that relies on previous one, intended to introduce concept of multiplex, it's advantages and drawbacks on the example of mC driven led-matrix. Shareware software for PC-side could be obtained from PC Press upon request. This software sends commands to mC over rs232 port. Controller is also equipped with DIN (XT-compatible) keyboard connector for direct control, without PC. Binary file (intended for eprom 2764) as well as source file is also, according to text obtainable from PC Press.

As for the original question, how to compile the source code:

I don't have the corresponding issues of PC Press at hand, but as I recall, around october-november 1995, Voja Antonic published on PC Extra (special issue), booklet 'Microcontroller 8031, architecture and programming', with references to intel ASM51 and Avocet assembler. It would not surprise me that author don't stride from this choice in articles you are interested in, and that some compiler-specific directives are giving you the trouble. My bet is - ASM51. Try it and give us info whether it worked?

I'm pretty sure that here on 8052 are some more experienced serbian-speaking '8052-wolves' that can answer your question more competent, but I've often saw some awkward comment about small amount of currency... So, my 2 dinars...

Best luck,
CN