Symptoms
I have increased max length size in the web.conf, but this still doesn't work.
I am also receiving the error attached in the K2 event logs.
I found the below article indicating these may be related and that there is a coldfix (4.6.11.9) that resolves the issue.
http://community.k2.com/t5/K2-blackpearl/I-see-a-bunch-of-errors-in-the-Event-Viewer-all-related-to-an/ta-p/86418
The below ticket also seems to be similar to my issue which this error is also mentioned.
https://portal.k2.com/support/report/snapshotnew.aspx?ID=100350
Diagnoses
Also requires a change in IIS.
Resolution
Cold fix and web.config change did not fix the issue, but may be a necessary change to enable the change in IIS.
Altering the IIS request filtering fixed the issue:
http://www.web-site-scripts.com/knowledge-base/article/AA-00696/0/Increasing-maximum-allowed-size-for-uploads-on-IIS7.html
