Random: SSL problem with lftp

Hi,
 
We are trying to use lftp to send large number of files (>2000) to large
number of system (>30) at the same time. The job is a simple loop:
 
foreach file
   foreach host
     send file to host &    # Job is backgrounded
   next host
   wait for all background jobs.
next file
 
The send script is simple:
   lftp host
   cd /path/to/dir
   pwd
   put file.txt
 
We are using RedHat builds: lftp 3.0.6, and vsftpd 2.0.1. We force SSL
encryption on password on the vsftp server. Usually, the transfer works
with no problem.We have very infrequent errors conditions (1 in ~4000
transfers). The error are random - each time they hit on a different
file. The error message:
 
cd: Fatal error: SSL read: wrong version number
 
which will cause the job to fail. We noticed that the "pwd" and the
"PUT" command that follow will work successfully establish the
connection.
 
Any help with the following will be appreciated:

*	What does the message mean ?
	*	Does anyone know/exprience the problem - have a
solution/workaround.
*	It looks as if retrying will solve the problem. Is there a
problem with the retry logic for the "cd". Is there a flag that we can
turn on to force retry ?

Thanks
Yair Lenga