[Zope] Error Messege

[Hadjimichael Nicos]

Hello,
I have a problem and i need your help.

When I try,to view for a first time, a dtml-method, which call ZSql query, i
get the Error message: 

Zope Error
Zope has encountered an error while publishing this resource. 

NameError

Sorry, a Zope error occurred


Then if i try to view this method again it's OK.I have the problem only at
the first time.

if anyone know something about this, please help,me.

Thank, a lot 

Nick.