DL Reader does not appear to run on Windows RT, only a full Windows 8 system.
Only other way is to purchase a program which remoes the DRM restriction.
epubee is free and does a good job.
DRM stripping should only be used where legally permitted,
or in some cases, where clearly ethically justified because the absurdities of Adobe's inept ADEPT DRM infrastructure prevent use within the intended ts&cs.