RUNA WFE is a open  source core for a commercial product
you can get training support, manual, etc by paying to developing company.
you can find  their web site in:

http://www.runa.ru/
http://wf.runa.ru/

you can find some documentations under:

http://wf.runa.ru/English/Docs/Docs.html

be careful wf.runa.ru is GPL
it means you have to open source  the product you want to use RUNA WFE on it.

if you just want a good workflow  engine and WFMC compliance is not important for you, we are working on YAWL, it is a good open source engine, and I can help  you to use it.

Could you let me know why you have selected YAWL? And how do you see jBPM? Would you bring a simple comparison between these two prodcuts here.

it was a hard decision
YAWL is not BPEL compatible.
YAWL is not WFMC compliant
YAWL is still under development, some how more complete than some workflow  engines but not as complete as some others specially the quality of code is still poor.

I think BPEL will be feature standard if bpel4people is implemented good.
WFMC is a bad standard in my opinion.

YAWL is theoretically correct.
YAWL is based on workflow patterns concept.
after studying JBPM, some WFCM compliant engines and some BPEL engines we decided to go over YAWL, because it was more theorically correct and more expanable than other engines.

I think jBPM is good for java developers to use inside a java system but not good for system which end users want to interact with workflow.

i dont suggest RUNA as a proper platform to be worked on , and as you may see the project  itself has been stopped for 1 year before , and also RUNA uses the very old version of jBPM that is not with a great functionalities . i suggest to use the new version of jBPM which has an editor itself and you may deploy your workflows on it as well .