A print processing system comprising: a print server for converting document data into a plurality of print data files based on document data size; a first storage server; a second storage server; and an image processing apparatus for obtaining the plurality of print data files, at least including a first print data file and a second print data file, and executing print processing, wherein the print server comprises: storing means for storing (S912, S917) the first print data file and the second print data file into the first storage server; generation means for generating an index file in response to an error occurring in processing for obtaining the second print data file from the first storage server, the index file including acquisition source information about the second print data file not yet obtained by the image processing apparatus, and storing means for storing the second print data file into the second storage server, and wherein the image processing apparatus comprises: an application configured to obtain the print data files from the first storage server via a first communication stream, a controller configured to obtain the print data files from the application via a second communication stream and perform print processing, and notification means for notifying the print server of information identifying the second print data file in response to the error occurring in the processing for obtaining the second print data file from the first storage server after obtaining the first print data file from the first storage server in the print processing of printing the print data files, wherein, in response to the error occurring, the application is configured to obtain the print data files from the second storage server via a third communication stream, while maintaining a state of connection between the application and the controller via the second communication stream, wherein the application is configured to transmit the print data files to the controller, using a continuous communication session implemented by the first communication stream and the second communication stream and in response to the error occurring, using a continuous communication session implemented by the third communication steam and the second communication stream. a print server for converting document data into a plurality of print data files based on document data size; a first storage server; a second storage server; and an image processing apparatus for obtaining the plurality of print data files, at least including a first print data file and a second print data file, and executing print processing, wherein the print server comprises: storing means for storing (S912, S917) the first print data file and the second print data file into the first storage server; generation means for generating an index file in response to an error occurring in processing for obtaining the second print data file from the first storage server, the index file including acquisition source information about the second print data file not yet obtained by the image processing apparatus, and storing means for storing the second print data file into the second storage server, and storing means for storing (S912, S917) the first print data file and the second print data file into the first storage server; generation means for generating an index file in response to an error occurring in processing for obtaining the second print data file from the first storage server, the index file including acquisition source information about the second print data file not yet obtained by the image processing apparatus, and storing means for storing the second print data file into the second storage server, and wherein the image processing apparatus comprises: an application configured to obtain the print data files from the first storage server via a first communication stream, a controller configured to obtain the print data files from the application via a second communication stream and perform print processing, and notification means for notifying the print server of information identifying the second print data file in response to the error occurring in the processing for obtaining the second print data file from the first storage server after obtaining the first print data file from the first storage server in the print processing of printing the print data files, an application configured to obtain the print data files from the first storage server via a first communication stream, a controller configured to obtain the print data files from the application via a second communication stream and perform print processing, and notification means for notifying the print server of information identifying the second print data file in response to the error occurring in the processing for obtaining the second print data file from the first storage server after obtaining the first print data file from the first storage server in the print processing of printing the print data files, wherein, in response to the error occurring, the application is configured to obtain the print data files from the second storage server via a third communication stream, while maintaining a state of connection between the application and the controller via the second communication stream, wherein the application is configured to transmit the print data files to the controller, using a continuous communication session implemented by the first communication stream and the second communication stream and in response to the error occurring, using a continuous communication session implemented by the third communication steam and the second communication stream.