Report Loading problem

hi..

i'm using crystal report 13.0.2000.0 with visual studio2010.

i've converted my reports from vs2008(c#) to vs2010(c#)...

when i was using crystal reports version10.5 with vs 2008 they are working fine and faster..

But crystal report 13.0.2000.0 are taking long time to load..after loading report viewer,if we export the report after 1 or 2 mins later it will show Error"Object reference not set to an instance of an object. "

but it works fine in development side, im getting this problem after hosting my application in server..