right before this error the following messages appear:
koha-upgrade-schema biblioteka
Upgrading database schema for biblioteka
Use of bare << to mean <<"" is deprecated at /usr/share/koha/intranet/cgi-bin/installer/data/mysql/db_revs/220600077.pl line 10.
Bareword found where operator expected at /usr/share/koha/intranet/cgi-bin/installer/data/mysql/db_revs/220600077.pl line 26, near "'4' class"
	(Missing operator before class?)
Bareword found where operator expected at /usr/share/koha/intranet/cgi-bin/installer/data/mysql/db_revs/220600077.pl line 31, near "'4' class"
	(Missing operator before class?)
Bareword found where operator expected at /usr/share/koha/intranet/cgi-bin/installer/data/mysql/db_revs/220600077.pl line 32, near "<h3>Outstanding"
	(Missing operator before Outstanding?)
Bareword found where operator expected at /usr/share/koha/intranet/cgi-bin/installer/data/mysql/db_revs/220600077.pl line 37, near "'4' class"
	(Missing operator before class?)
Bareword found where operator expected at /usr/share/koha/intranet/cgi-bin/installer/data/mysql/db_revs/220600077.pl line 38, near "<h4>Debts"
	(Missing operator before Debts?)
Bareword found where operator expected at /usr/share/koha/intranet/cgi-bin/installer/data/mysql/db_revs/220600077.pl line 40, near "% IF borrower"
	(Missing operator before borrower?)
Bareword found where operator expected at /usr/share/koha/intranet/cgi-bin/installer/data/mysql/db_revs/220600077.pl line 42, near "<th>Charge"
	(Missing operator before Charge?)
Use of uninitialized value $description in sprintf at /usr/share/koha/lib/C4/Installer.pm line 804.