CRCS errors on serial E1 links

Dear Experts

the router has been taking hits , and iam experiencing CRC errors on the serial E1 link of the router, the serial E1 link is connected to another router via microwave links
- below are the follwoing outputs whi could analyze the problems

sh log
-  Feb 15 22:57:05.406: %CONTROLLER-5-UPDOWN: Controller E1 0/0, changed state to d
own (AIS detected) <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<
Feb 15 22:57:07.406: %LINK-5-CHANGED: Interface Serial0/0:0, changed state to re
set <<<<<<<<<<<<<<<<<<<<<<<<<< 
Feb 15 22:57:08.406: %LINEPROTO-5-UPDOWN: Line protocol on Interface Serial0/0:0
, changed state to down <<<<<<<<<<<<<< 
Feb 16 03:00:17.405: %CONTROLLER-5-UPDOWN: Controller E1 0/0, changed state to u
p
Feb 16 03:00:19.405: %LINK-3-UPDOWN: Interface Serial0/0:0, changed state to up
Feb 16 03:00:20.569: %LINEPROTO-5-UPDOWN: Line protocol on Interface Serial0/0:0
, changed state to up
==========================

UCC-Plant-Router#sh processes cpu history

UCC-Plant-Router   03:03:35 PM Monday Feb 16 2009 LCT


    4477777777777777777777888884444488888444447777755555444448
    8899999888888888899999000004444411111888881111188888999994
100
 90
 80   *************************     *****                    ***
 70   *************************     *****     *****          ***
 60   *************************     *****     **********     ***
 50 ***************************     ****************************
 40 ************************************************************
 30 ************************************************************
 20 ************************************************************
 10 ************************************************************
   0....5....1....1....2....2....3....3....4....4....5....5....
             0    5    0    5    0    5    0    5    0    5
               CPU% per second (last 60 seconds)

    8888888887888888888888988888888888888888898888889888888888
    4321200009200102022311035422201422020220222005526032212201
100                                                 *         *
 90                       * *                *   ** *         *
 80 ************************************************************
 70 *#****************#****###*##**#*##*****##******************
 60 *####**###**###*####**####################*###*##*#*##*#*##*
 50 ############################################################
 40 ############################################################
 30 ############################################################
 20 ############################################################
 10 ############################################################
   0....5....1....1....2....2....3....3....4....4....5....5....
             0    5    0    5    0    5    0    5    0    5
               CPU% per minute (last 60 minutes)
              * = maximum CPU%   # = average CPU%
                           1                               111  1
    9999998988999899898997909984999658997999899557789697976000850999646564
    6999496407999690801928609916999155490973396320999498945000890290117930
100 **** *    *** *    *  ****  ***    * **  **     * * *  ***  * *        *
 90 ******** ********* ** ****  ***  *** *** **    ** * *  **** ****      **
 80 *************************** ***  *** ******   *** ***  **** ****      **
 70 ***#*********************** ***  **********  **** ********* ****  *   **
 60 ***#*#*****####************ ***************  ******************** *** **
 50 #*####****######************************************************* *** **
 40 #*####***########*******************************************************
 30 #######*##########******************************************************
 20 ####################****************************************************
 10 ##################################################################**####
   0....5....1....1....2....2....3....3....4....4....5....5....6....6....7.
             0    5    0    5    0    5    0    5    0    5    0    5    0
                   CPU% per hour (last 72 hours)
                  * = maximum CPU%   # = average CPU%
-===================================
UCC-Plant-Router#sh interfaces Serial0/0:0 | inc CRC
      123 input errors, 47 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort <<<<<< 
- the CRCs has been increasing with the same rate every 3 days i clear the counters

- my question is as follows

- is there any troubleshooting steps to analyze these kind of problems
- if i need to test or perform an end-to-end loop test from the router interface, what configuration steps can be done on the router wan interface and how do  i dispaly the output from these tests bearing in mins that wan link that conects the 2 sites is a microwave links without any csu/dsu or dce being involved in middle
- the process-cpu utlization output seems to be high as per above but does this mean that this should reflext on the connectivity , or should result in the link flapping between the 2 sites ?