I have the same problem.
I fixed all the paths in the psa.conf already according to the actual locations of the files on my server and restarted psa.
I'm not sure what the problem is now.
Here is the first part of the latest error messages:
# /usr/local/psa/admin/sbin/statistics --calculate-one --domain-name=mydomain.com
Create/Update database for config "/usr/local/psa/etc/awstats/awstats.mydomain.com-http.conf" by AWStats version 6.8 (build 1.910)
From data in log file "-"...
Phase 1 : First bypass old records, searching new record...
Searching new records from beginning of log file...
Jumped lines in file: 0
Parsed lines in file: 0
Found 0 dropped records,
Found 0 corrupted records,
Found 0 old records,
Found 0 new qualified records.
sh: /usr/bin/awstats_buildstaticpages.pl: /usr/bin/perl^M: bad interpreter: No such file or directory
statistics: Unable to execute /usr/bin/awstats_buildstaticpages.pl -awstatsprog=/var/www/awstats/awstats.pl -configdir=/usr/local/psa/etc/awstats -config=mydomain.com-http -dir=/var/www/vhosts/mydomain.com/statistics/webstat/current
System error 2: No such file or directory
statistics: Unable to execute /usr/bin/awstats_buildstaticpages.pl -awstatsprog=/var/www/awstats/awstats.pl -configdir=/usr/local/psa/etc/awstats -config=mydomain.com-http -dir=/var/www/vhosts/mydomain.com/statistics/webstat/current
System error 2: No such file or directory