Thanks for your bug reports.
I will try to remove the bugs, maybe this weekend.
If I give export all, so I can select folder, but I cant create new folder,so I must create it manualy.
Yeah thats a pre-built FolderBrowserDialog, i cant change that.
Try installing the newest .net Framework or something, because when i click that "export all", there's a button "Create new folder" in the bottom left corner of the dialog.
EDIT: I tried extracting all files from flevel.lgp with Highwind and uncompress them at the same time, then make a new archive with those files, and Highwind did not get an exception.
EDIT2: Theres no crash for me when extracting flevel with lgptools and decompressing and then creating an archive with those files with highwind.
But i didnt try if the game works now, i think it will crash because it looks for compressed files.
EDIT3: Yes, FF7 cant load the field backgrounds when they are uncompressed in flevel.lgp, ive checked that.