Error with en-common.rws when add a word to dictionary

Hi 

International Ispell Version 3.1.20 (but really Aspell 0.50.5)
I am using a Perl interface to Aspell (Text::Aspell). 


I am trying to add a word to an personal dictionary. I have the 
following options:

lang=en_GB
dict-dir=/var/www/cgi-bin/dictionaries
personal=testdict.dict
size=10

Then there is a method to "add_to_personal":

$speller->add_to_personal($wordToAdd) || die "Failed to add 
$wordToAdd: " . $speller->errstr;

When it gets to the line above I get the following error:

Failed to add foobarbaz: The file "/var/www/cgi-bin/dictionaries/en-
common.rws" is not in the proper format.
 
The only discrepancy I can see comes from strings (rowl 1.{10,4})

>strings en-common.rws
aspell default speller rowl 1.10
phonet
...

>strings testdict.dict
aspell default speller rowl 1.4
phonet

Does anybody know if this is the source of the error and perhaps some 
suggestion on how I resolve it?

TIA,
Dp.