Web Part Deployment Error : This solution contains resources scoped for a web application

I recently created a web part , and faced a problem in deploying it.
The error was :
“this solution contains resources scoped for a web application and must be deployed to one or more web applications“

After searching the web and trying many things the problem solved , what i did is change the deployment command from this :
STSADM -o deploysolution -name SomeWebPart.wsp -local -allowGacDeployment

To this :

STSADM -o deploysolution -name SomeWebPart.wsp -local -allowGacDeployment -allcontenturls

basically what i did is adding a new option (-allcontenturls).

Its description from Microsoft:
Equivalent to deploying the package to all nonadministrative virtual servers that are in the farm.