Sorry for the misleading Subject content, simply replied to another
question and forgot to change this.

I now know the answer having received a reply for Lsoft - see below.
Thanks 
Martin

t looks like you have a license with capacity of 5 units and have
reached that limit.  License points are detailed at:
<http://www.lsoft.com/manuals/lsv-faq.stm#_Toc159583751>, which I'll
also reproduce here:

5.28. How do license points work? 

How do LISTSERV's license points work? For instance, if I have a 10
point LAK (UNITS=10), why can't I make 10 lists? Isn't it one point per
list?

(This question applies only to sites that have graduated LAKs. If your
LAK has "UNITS=0" then it is non-graduated (ie, unlimited capacity).)

The answer to the question is, "it depends". With a 10-point LAK you can
make 10 lists as long as they have 150 or fewer subscribers each. But if
you have lists larger than 150 subscribers, you start using multiple
points per list. 
The subscribers-to-points scale is as follows:

If you have this many subscribers on a given list:
then you need this many points for the list:
 
0 - 150
 1
 
151 - 300
 2
 
301 - 500
 3
 
501 - 1000
 4
 
1001 - unlimited
 5
 
Thus if you have a list with 141 subscribers, a list with 673
subscribers, and a list with 2530 subscribers, you need a total of 10
points (1 + 4 + 5) to run the lists, and if you have only a 10 point LAK
you will not be able to make more lists unless you purchase more
capacity.

Note: This scale does not apply to sites that have LAKs with
SCOPE=PERLIST, in which case one list == one point regardless of size.
Typically L-Soft sells this type of LAK only to ISPs.

If you do not know how many points you currently have in use, you can
issue the command SHOW POINTS ALL to get a detailed breakdown.

If you want to increase your license points, you'll need to contact your
Sales rep to discuss new licensing.  Thanks.