crystal report pdf generation error

Question

rptDoc.ExportToDisk(ExportFormatType.PortableDocFormat, target+ "\\images.pdf");


"Error in File C:\DOCUME~1\INTERL~1\ASPNET\LOCALS~1\Temp\temp_f7c 02ce5-f718-4dd9-bc64-ce29432383f0.rpt: The request could not be submitted for background processing.

i am getting this error. for few folder data its generating pdf successfully. but on some folder its giving this error
how to resolve the error