I am trying to convert ".ai" files to another format without buying adobe illustrator.

I use Inkscape and it does open some files; however, I have many I cannot open with Inkscape. I have also tried many other approaches: including changing ".ai" to ".pdf" etc., gimp, ReaConverter, Scribus, XnView, advanced Tiff editor, doc converter express, able postscript converter, and a few others.

I have several files that I would like to use, but I cannot convert them. Some ".ai" files open, but others do not. The files are from different sources so I cannot find a pattern or what make them different.

Can anyone help me find a way to convert ".ai" files? I am not looking to have to send files to someone to convert (there are too many). I am looking for a way to convert the files so I can use them.

I have read through the forum and several other areas.

I have tried to use "uniconverter" and no luck; I have a sample file if someone wants to try it.

Do you know what version of Illustrator they were created with?