HNDSOCK failed to lock tables/HNDSOCK failed to open

[karpa13a]

found some strange in mysqld.log:
HNDSOCK failed to lock tables 0x3cd13f0
HNDSOCK failed to lock tables 0x3cd13f0
HNDSOCK failed to lock tables 0x3cd13f0
HNDSOCK failed to lock tables 0x3cd13f0
HNDSOCK failed to open 0x3cc9df0 [database] [table] [1]
HNDSOCK failed to open 0x7f2e9310f910 [database] [table2] [1]
HNDSOCK failed to open 0x3cbbab0 [database] [table] [1]
HNDSOCK failed to open 0x3ccd8f0 [database] [table] [1]
HNDSOCK failed to open 0x3cc62f0 [database] [table] [1]
HNDSOCK failed to open 0x3cc27f0 [database] [table2] [1]

wtf?) what kind of data returned to this wuery? or this means bogus query?

[karpa13a]

does HS plugin compatable with innobackupex? or any magic args for online backup required?

[karpa13a]

this errors written to mysql.log, when innobackupex trying to lock all tables, output from innobackupex like:

...
110712 16:02:36  innobackupex: Continuing after ibbackup has suspended
110712 16:02:36  innobackupex: Starting mysql with options:  --defaults-file='/var/tmp/inst75.cnf' --user='root' --socket='/tmp/inst75.sock' --unbuffered --
110712 16:02:36  innobackupex: Connected to database with mysql child process (pid=32527)
>> log scanned up to (86248165)
110712 16:02:40  innobackupex: Starting to lock all tables...
>> log scanned up to (86248165)
....
>> log scanned up to (86248165)
...

and last line repeated until ctrl+c pressed. mysqld after ctrl+c need to be restarted. all tables in locked state.
to repeat, create temp table with few tables and data in it, access data few times (up to 5 min) and after try to use innobackupex to hotbackup it.
command line: innobackupex --no-timestamp --user root --socket=/tmp/inst75.sock --defaults-file=/var/tmp/inst75.cnf /var/tmp/inst75/

inst75.cnf:

[mysqld]
datadir=/var/lib/mmysql/inst75
innodb_log_file_size=64M