Failed to save mailbox : Missing file to open at sendmail::../web-lib-funcs.pl line 1819

Hello,
Yesterday we do a webmin and perl update and now we can not add new emails addresses in virtualmin.

When we try to add a new email account appears the next message:
Failed to save mailbox : Missing file to open at sendmail::…/web-lib-funcs.pl line 1819

webmin 1.310
virutalmin 2.611

Any idea?