I found in the past few weeks that management (and some non-management coworkers as well, but less so) have a tendency to demand things to be done without specifying how they want it done.

This doesn't have to be a bad thing. If someone gives you a task without specificing how to do it, you might consider that bad management. However, you could take a different point of view. Perhaps you are given responsibility. Perhaps you have earned some respect or trust. Don't panick.

And once that is done, they see another thing which could be done in another way - the last time I put a simple presentation on the web for download, I got requests to change file format, link text, link placement etc. over a time span of three weeks...

And this is strange? Seems perfectly normal in a process of creating a product. Writing good specs is very hard. Knowing what you want and formulating it in such a way a good spec can be written is even harder. Besides, people change their minds. Remember the second rule of Perl development: Larry can change his mind anytime (Rule 1 being: Larry is always right).

Sometimes I wonder... is it really that management people just can't express themselves and communicate properly, or we tech people don't understand them?

If all tech people could express them very well, and communicate properly, we wouldn't need Damian to write exergesis, would we? Then Larry's apocalypses would be clear for everyone, and the perl6-language list would only have postings of code implementing perl6, without the need for discussion.

Apart from writing specs down and have them approved, how do others work around this kind of problem? Is it a problem at all in other companies?

It would only be a problem if they expect you to meet deadlines, and they keep putting in change requests all the way to the deadline.

Abigail