Perl: empty DBI::err and DBI::errstr

I need help.

I use perl 5.8.0 and connect to Adabas 12 database via DBI and
DBD::AdabasD.

Everything works fine, but I do not get error messages if (for
example) a prepare or execute statement fails.
Both, DBI:err and DBI::errstr stay undefined. If I use the Adabas
specific variables $DBD::AdabasD::err and $DBD::AdabasD::errstr I get
the error messages.

Has anybody seen this kind of error before? 
Does anybody has a solution?

Thanks for Your help.