[pgrouting-users] Help with Routing from Point to Point

[agentsees]

Hello!

I am searching for a solution to route from a Point on a line to another 
point on a line. I wonder why this hasnt been implemented yet in 
pgrouting, because i think its (one of the) most used feature! What i 
got till now is routing with different algorithms on Openstreetmap data 
from and to vertices and edges. I have sucessfully calculated the 
nearest points on the nearest edge to my start and endpoints. I tried to 
fill the missing last part with the tutorial from here : 
http://pgrouting.postlbs.org/wiki/LoadingtheCode5
But i could not get it working. The function throws errors on the 
following SQL statement:

SELECT 
astext(give_we_wkt(".$startEdge['gid'].",".$ergebnis_nebengeometrie_anfang_gid.",'".
$point_on_line_anfang."'))

It says, that st_intersects is neither false nor true on:
SELECT INTO p ST_intersects(line,buffer($3,1));

I think the problem is the creation of the linestring ('line') in the 
functioncode, because i can see errors which tell me that "||" is not an 
allowed operator.
The linestring itself remains empty and maybe thats why the function fails.
Has somebody an idea how to fix this?

Is there no other / easier solution to route from one point to another?

Thanks for answers in adavance!

J. Weskamm