I have a problem. When I start pdfLatex using the package media9, there comes this error:
The required file tex\latex\l3experimental\l3str\l3regex.sty is missing.
So, I have downloaded the package l3experimental, but there is no path like this: l3experimental\l3str\l3regex.sty and l3regex.sty doesn't exist (only l3regex.dtx).
So, I have adjusted accordingly the path and renamed the file format into sty, but the error doesn't disappear.
Can You help me, please?