UDK Content Browser Red Border error and green arrow doesn't work for anything Help

[00peteee00]

I have been working on a rain system for this map and i have had a problem when it comes to linking the 'MaterialinstanceActor' to the 'MaterialInstanceConstant'
I select the 'MaterialInstanceConstant' in the Content Browser and then click the green arrow in the properties of the 'MaterialinstanceActor' to apply it
and then it comes up with the second picture below as an error. It has happened other times i have tryed to use the green arrow when just applying normal materials,
and there is a permanent Red box around the Content browser window as seen in the first image. This is on the march version, i have tried opening other versions
and the problem isn't there but i can't get my map to load on older version. Please help hopfully i'm just being silly and its an easy fix

appreciate it guys !

[Lexluthor1]

I have been working on a rain system for this map and i have had a problem when it comes to linking the 'MaterialinstanceActor' to the 'MaterialInstanceConstant'
I select the 'MaterialInstanceConstant' in the Content Browser and then click the green arrow in the properties of the 'MaterialinstanceActor' to apply it
and then it comes up with the second picture below as an error. It has happened other times i have tryed to use the green arrow when just applying normal materials,
and there is a permanent Red box around the Content browser window as seen in the first image. This is on the march version, i have tried opening other versions
and the problem isn't there but i can't get my map to load on older version. Please help hopfully i'm just being silly and its an easy fix

appreciate it guys !

The red box around the content browser window is in my March build but doesn't cause any problems..Its just a new feature I would have thought!
I don't have a solution for your problem but would suggest that red box has nothing to do with it...

[Solid Snake]

What does the log say?