Production Jobs failing!

Question

One of the sales orders report is run as a background job,which extratcs large volume of the data. Jobs are failing frequently and below are some errors:
Error Log -1
Short text
    Error when writing to the file "/appl/data/log/outbound/tst_pmd_erp_201
What happened?
    Resource bottleneck
    The current program "ZPS_XXXX" had to be terminated because
    a capacity limit has been reached
Error Log -2
Short text
    Unable to fulfil request for 20000 bytes of memory space.
What happened?
    Each transaction requires some main memory space to process
    application data. If the operating system cannot provide any more
    space, the transaction is terminated.
Error Log -3
Short text
    No more storage space available for extending an internal table.
What happened?
    You attempted to extend an internal table, but the required space was
    not available.
Performace Approach already use:
1) Use of packet Size of 1000 when reading data
2) Use of stament Free to clear the Global work areas,gloabal internal tables and also local  workarea and internal tables.
Most of the time Dump occurs when we write the files to the Unix Folder (About 70,000 records).

Answer 1

Short Dump Info:
Short text
    Error when writing to the file "/appl/data/backlog/sapwork/cad_finbacklog_erq_2
What happened?
    Resource bottleneck
    The current program "ZPS_BACKLOG_NEW_READ" had to be terminated because
    a capacity limit has been reached.
What can you do?
    Note which actions and input led to the error.
    For further help in handling the problem, contact your SAP administrator
    You can use the ABAP dump analysis transaction ST22 to view and manage
    termination messages, in particular for long term reference.
Error analysis 
    An exception occurred that is explained in detail below.
    The exception, which is assigned to class 'CX_SY_FILE_IO', was not caught in
    procedure "WRITE_TO_BUFFER" "(FORM)", nor was it propagated by a RAISING
     clause.
    Since the caller of the procedure could not have anticipated that the
    exception would occur, the current program is terminated.
    The reason for the exception is:
    An error occurred when writing to the file
     "/appl/data/sapwork/cad_finbacklog_erq_20111012_152913.dat".
    Error text: "Missing file or filesystem"
    Error code: 52
    Last error logged in SAP kernel
    Component............ "EM"
    Place................ "SAP-Server paerqas1_ERQ_52 on host paerqas1 (wp 29)"
    Version.............. 37
    Error code........... 7
    Error text........... "Warning: EM-Memory exhausted: Workprocess gets PRIV "
    Description.......... " "
    System call.......... " "
    Module............... "emxx.c"
    Line................. 2222
The error reported by the operating system is:
Error number..... 52
Error text....... "Missing file or filesystem"
How to correct the error
    If the error occures in a non-modified SAP program, you may be able to
    find an interim solution in an SAP Note.
    If you have access to SAP Notes, carry out a search with the following
    keywords:
    "DATASET_WRITE_ERROR" "CX_SY_FILE_IO"
    "ZPS_BACKLOG_NEW_READ" or "ZPS_BACKLOG_F01_READ"
    "WRITE_TO_BUFFER"
    If you cannot solve the problem yourself and want to send an error
    notification to SAP, include the following information:
    1. The description of the current problem (short dump)
       To save the description, choose "System->List->Save->Local File
    (Unconverted)".
    2. Corresponding system log
       Display the system log by calling transaction SM21.
       Restrict the time interval to 10 minutes before and five minutes
    after the short dump. Then choose "System->List->Save->Local File
    (Unconverted)".
    3. If the problem occurs in a problem of your own or a modified SAP
    program: The source code of the program
       In the editor, choose "Utilities->More
    Utilities->Upload/Download->Download".
    4. Details about the conditions under which the error occurred or which
    actions and input led to the error.
    The exception must either be prevented, caught within proedure
    "WRITE_TO_BUFFER" "(FORM)", or its possible occurrence must be declared in the
    RAISING clause of the procedure.
    To prevent the exception, note the following:
Information on where terminated
    Termination occurred in the ABAP program ZXYZ - in
     "WRITE_TO_BUFFER".
    The main program was "ZXYZ".
    In the source code you have the termination point in line 9900
    of the (Include) program "ZXYZ".
    The program "ZXYZ" was started as a background job.
    Job Name....... "LOG RWT FINBKLG"
    Job Number..... 15102300
    The termination is caused because exception "CX_SY_FILE_IO" occurred in
    procedure "WRITE_TO_BUFFER" "(FORM)", but it was neither handled locally nor
     declared
    in the RAISING clause of its signature.
    The procedure is in program "ZXYZ"; its source code begins in
     line
    9592 of the (Include program "ZXYZ01 ".
9898       LOOP AT gt_output_unix ASSIGNING <lfs_output_unix>.
9899         MOVE <lfs_output_unix> TO lx_string.
>>>>>         TRANSFER lx_string TO p_fname.
9901         CLEAR lx_string.
9902      ENDLOOP.
Appreciate your help.