PowerDNS : libpipebackend.so no such file or directory

Hi there, i was using powerdns to handle authoritative queries, i got some errors in my powerdns log file, you can find it below. How to solve this error?

Mar 14 14:33:36 ns1 pdns[38122]: Guardian is launching an instance
Mar 14 14:33:36 ns1 pdns[38122]: Reading random entropy from ' /dev/urandom' 
Mar 14 14:33:36 ns1 pdns[38122]: Unable to load module ' /usr/lib64/pdns/libpipebackend.so' : /usr/lib64/pdns/libpipebackend.so: cannot open shared object file: No such file or directory
Mar 14 14:33:36 ns1 pdns[38122]: dnsbackend unable to load module in pipe
Mar 14 14:33:37 ns1 pdns[38091]: Our pdns instance exited with code 1
Mar 14 14:33:37 ns1 pdns[38091]: Respawning