Missing <adminui>\standalone\deployments\castylesr5.1.1.ear.dodeploy & <adminui>\standalone\deployments\iam_siteminder.ear.dodeploy files could cause this behaviour.
There are two ways you can fix this problem.
1. Create empty files called castylesr5.1.1.ear.dodeploy & iam_siteminder.ear.dodeploy files under \\adminui\standalone\deployments\ directory.
And start 'SiteMinder Administrative UI' service.
This *.dodeploy would deploy the service and you would be able to access the /iam/siteminder/* resources.
2. Copy castylesr5.1.1.ear.deployed & iam_siteminder.ear.deployed files from backup. Or create files with following contents.
The contents of files could have as below;
Content(specify the .ear filename that need to deploy in single line): castylesr5.1.1.ear
Content(specify the .ear filename that need to deploy in single line): iam_siteminder.ear