sitecore - Can't Open Web forms for marketers Form Designer or Security Manager -

i have had wffm running on sitecore instance while, has stopped working. when go "form designer" on existing form, standard sitecore "the requested document not found" page.

requested url: /applications/modules/web

user name: sitecore\admin

site name: shell

if page trying display exists, please check appropriate prefix has been added ignoreurlprefixes setting in web.config.

note requested url stated /applications/modules/web instead of /applications/modules/web forms marketers.

a lot of development has occurred on site recently, i'm not sure when started happening.

additional: info:

• folder , file permissions correct.
• i've tried reinstalling wffm package, , made sure files in place.
• several processors have been added httpbeginrequest pipeline, removed them test if cause - weren't.
• i haven't upgraded sitecore since wffm working , version correct.
• no errors logged

edit

this seems affecting sitecore security editor:

requested url: /appl

user name: sitecore\admin

site name: shell

if page trying display exists, please check appropriate prefix has been added ignoreurlprefixes setting in web.config.

edit 2

further investigation making me think related requested url. thought the "not found" page displaying requested url incorrectly. however, if attempt goto mysite.com/sitecore/shell/applications/fake folder spaces/fake page spaces error message:

requested url: /applications/fake folder spaces/fake page spaces

user name: sitecore\admin

site name: shell

if page trying display exists, please check appropriate prefix has been added ignoreurlprefixes setting in web.config.

as can see requested url correct in error message. in relation problem, think maybe sitecore requesting wrong url in first place.

additionally if go go following url typing directly browser, security editor opens expected: mysite.com/sitecore/shell/applications/security/user-editor

this quite old thought i'd provide update else encounters problem.

unfortunately, sitecore support weren't able beyond pointing out setting addaspxextension attribute 'true' in link provider seemed solve problem. may have been acceptable except extensionless urls important customer.

in end had amend link provider addaspxextension set 'true' in web config, , set false inside getitemurl method specified sites only.

so whenever context site 'shell' or 'admin' etc, extensions added default, switched off in main website.

of course, work around. still don't know how fix problem