Create cotation not possible (Postgresql 5.2.1 version)

The last problem, not blocant is in log file this error:
2016-01-25 16:18:01.563 ***** ERROR ***** Exception-[22P02] SQLSTATE[22P02]: Invalid text representation: 7 ERROR: invalid input syntax for type numeric: ""
LINE 1: ...reference,''),' - ',name,' (',coalesce(fullAmount,''),')') a...
^
2016-01-25 16:18:01.563 ***** ERROR ***** For query : select id as id, concat(coalesce(reference,''),' - ',name,' (',coalesce(fullAmount,''),')') as name from bill where (1=1 and idle=0 and bill.paymentDone='0' and bill.done='1') order by bill.name
2016-01-25 16:18:01.563 ***** ERROR ***** Strack trace :
2016-01-25 16:18:01.563 ***** ERROR ***** #0 Sql->query called at [/var/www/html/model/persistence/SqlList.php:227]
2016-01-25 16:18:01.563 ***** ERROR ***** #1 SqlList->fetchListWithCrit called at [/var/www/html/model/persistence/SqlList.php:76]
2016-01-25 16:18:01.563 ***** ERROR ***** #2 SqlList->getListWithCrit called at [/var/www/html/tool/html.php:95]
2016-01-25 16:18:01.563 ***** ERROR ***** #3 htmlDrawOptionForReference called at [/var/www/html/view/objectDetail.php:1415]
2016-01-25 16:18:01.564 ***** ERROR ***** #4 drawTableFromObject called at [/var/www/html/view/objectDetail.php:251]

I think i dont have initialised default values. But the question is what is default value ?

Hi,
It is when i record a new cotation. I think no, bug is present.

Thanks for your support.