Hi guys, I wanted to inform you about status of my problem. I recovered the password after 6 days of automatic trying the type of passwords I use using multicore CPU & GPU. (Thank god I am a developer)
Firstly I thought that it was a bug in 7z because archive programs such as winrar gave me error messages like "corrupt archive?". So I thought there was a bug in 7z format. I still think this is an issue you should fix. 7z should give more specific error message.
It was complete stupitidy of me to forget the password. Thank you for your support and responses.