[UPDATE]: solved ! An update using Baltic Theatre updater it is enough to solve the issue. Sorry about the post.
It seems that just on the Baltic theatre there is a weird formatting issue preventing EZBoard tool to generate kneeboards.
I tested EZBoard with Middle East 128 and Korea and it works.
More details here: https://forum.falcon-bms.com/post/370460
I also tried the workaround suggested here: https://discord.com/channels/263470085560205313/681294232325062801/1083120972699291738 but I keep getting EZBoards errors anyway.
Anyone knows a workaround ?