page cannot be displayed while executing WD Application through Transaction Code in ECC

Hi

I am currently facing a very typical issue.

Scenario-->

I have two webdynpro application.

One WD application I am running from Transaction Code in ECC and another one i am calling from this webdynpro application by clicking on a email id hyper link. (Link To Action)

Issue-->

I can able to trigger the second application from the first one which i run from ECC but surprisingly when the second screen is active ,if I am doing any action in the ECC application,i am getting a error "Page Cannot be displayed" and the page is gone and there is no dump is getting generated in ST22.

Need to understand why this is happening.

Point 1-->I notice that if i am closing the second screen and then doing any action in the application active in ECC i am not getting this error.So what i believe is when both the screen is active and i am doing any action in the first screen this error is getting generated.

Point 2-->I run the first application from portal and then trigger the second screen and found out that it is working fine if I am doing any activity in the first screen, though it is not a ideal situation.Customer is going to execute the first screen from the ECC from which they are going to trigger the second screen.

Please suggest the input and if required I can share the screen shot as well.

Thanks in advance for the support.

Cheers

Jay