Hi

I have a problem with python 2.6, when i try to process strings with
triple-quoted string literal i get an error:

a='a''a' #1 double quoted Ok

a='a''''a' # 2 Ok

a= 'a''''''a' # 3 doble quoted -- SyntaxError: EOF while scanning
triple-quoted string literal

a= 'a''''''''a' # 4 ok

a='a''''''''''a' # 5 same error impair doble quoted

a='a''''''''''''a' # 6 Ok...............

a... #7 error..................

All your samples explain easily if you consider that two adjacent string 
literals are joined together. (You seem to consider that "double quote" 
is a way to insert a quote character. It's not; Python is not Pascal or 
SQL)

Your first two examples become:
a='a''a'   two adjacent strings == 'aa'
a='a''''a' three adjacent strings ('a' + '' + 'a') == 'aa'

The third is an error:
a='a''''''a' one string ('a') followed by the beginning of a "triple 
quoted string" (''') which content starts with the characters (''a') but 
does not have a matching (''') to finish the string, hence the Syntax 
error.

... and so on. Please have a look at http://docs.python.org/reference/lexical_analysis.html#string-literals