qmail, spamassassin, vmailmgr and PDF attachments problems localdelivery problems...

Hello, i am having trouble with some messages when spamassassin is
enabled. Problem occurs when message
contains PDF attachments (maybe other file types, but i am not sure).

my spamassassin conf: local.cf

required_hits 10
report_safe 0
rewrite_header Subject [SPAM]

user_scores_dsn DBI:mysql:data:localhost:mysql_socket=/tmp/
mysql41.sock
user_scores_sql_username user
user_scores_sql_password pass

..qmail-user file:

|/usr/bin/ifspamh user@example.com user@example.com
|/var/qmail/bin/preline -d /usr/bin/spamc -f -u user@example.com | /
usr/bin/filepipe /opt/vmailmgr/bin/vdeliver

In maillog i have only entry that that delivery of specified message
is started and that is all. Message got stuck in
local mail queue.

When i change .qmail-user file to:

|/opt/vmailmgr/bin/vdeliver

everything works. I tried everything that i can think off. I am new to
qmail configuration, and i didn't installed qmail on this system.

Thanks for any suggestions...