Hi Minakshi Soni,
SAP MII 14.0 is fine when you work in JAVA 7 environment.
I am also facing the same issue, when i updated my JRE 1.6 Update 31 to JRE 1.7 Update 45 its working fine.
For applet issue try to implement SAPUI5 in your MII, it will help you to resolve your applet loading issue.
Refer SAP UI5 from below link:
https://sapui5.netweaver.ondemand.com/devguide.html
https://tools.hana.ondemand.com/#sapui5
Hope this info will help you, all the best.
Regards,
Santhosh K