Yes , i resolved this problem by recreating the Qlikview document again. the simple way is to use <document name>-prj method to recreate the document to get the same chart id's , so not much of work is required.
this would resolve the unspecified error as a workaround. There are no technical fixes available to specific unspecified error issues so far. different clients have faced different problems in their environment or the document could have been possibly corrupted especially in terms of allocating memory for array etc.