subject URI contextual filter fails

Hello.

first of all: fantastic module. This is definately the future, and i have a feeling i will use this module quite a bit in months to come.
so, to my problem:

I tried browsing for others having the same problem, since i (as many before me) followed the ibm dev tutorial (http://www.ibm.com/developerworks/library/wa-datasets/).

It looks like its working almost as expected, but i can not get the DBPedia block to show correctly.

error message:
Notice: Undefined index: subject in sparql_views_handler_argument->query() (line 70 of /home/orkjernc/public_html/sites/all/modules/sparql_views/handlers/sparql_views_handler_argument.inc).
Notice: Undefined index: rdf_mapping in sparql_views_handler_argument->query() (line 75 of /home/orkjernc/public_html/sites/all/modules/sparql_views/handlers/sparql_views_handler_argument.inc).

i did a lot of troubleshooting and first found out that i can reach dbpedia just fine, as it displays info when omitting the filter.

then i found out that if i use some other field as contextual filter (as the case is for the "related projects" block) it seems to work. i used http://dbpedia.org/ontology/affiliation as mapping for a new field - just to test, and now got results back from both blocks.

i even tried to php code the field as argument ($node->field_123['und'][0]['safe_value']). same error message.

then i tried to use uri as contextual filter for the other block ("related projects") resulting in this view also failing.

i am not sure if this is a bug, or if i am doing something wrong. but i have tried this on a fresh install on 2 different setups now, all modules up to date. seems like views are failing when the uri is the contextual filter.