psadump error: bad file descriptor

[kenzor]

while executing the following:

/usr/local/psa/bin/psadump --nostop --nostop-domain -z -f [url]ftp://username:password@some.ip.address/[/url] | split -b1000m

i am receiving the following error at different points during the backup process:

An error was occured during execution: "/bin/tar -cz  --exclude='./web_users' --exclude='./tmp' --exclude='./etc' --exclude='./lib' --exclude='./bin' --exclude='./usr' --exclude='./subdomains' --exclude='./conf/httpd.include*'  -f - -C '/home/httpd/vhosts/somedomain.com.au' conf error_docs pd statistics "

Unable to save dump file: Bad file descriptor

often it fails while backup the mail, then the line before the 'unable to save' is different.

any ideas?