After those 700 days on the system monitors CPU "user" load is always zero. The CPU is mostly shown busy (near 100%) in "system". Before that everything worked fine. I am on openSUSE 12.1 32 bit. My ksysguardd version is 4.7 as supplied by the openSUSE repositories. As far as I can tell all newer version still have this bug

Reproducible: Always

Steps to Reproduce:
1. Boot your system (32 bits)
2. Wait ~700 days ;-)
3. Launch any KDE utility showing CPU load

Actual Results:  
CPU "user" load is zero, CPU "system" load very high

Expected Results:  
Show plausible amount of CPU "user" and "system" loads

This is the head of my current /proc/stat:
cpu  4425217554 1286866 581986284 1173412658 3046616 22233 6309211 0 0 0
cpu0 4425217554 1286866 581986284 1173412658 3046616 22233 6309211 0 0 0

Note that the first number is more than 2^32!

These are the changes I made to ksysguardd/Linux/stat.c that seem to fix this:
***************
*** 20,25 ****
--- 20,27 ----
   * stat.c is used to read from /proc/[pid]/stat
  */

+ #include <inttypes.h>
+
  #include <sys/types.h>
  #include <sys/stat.h>
  #include <sys/time.h>
***************
*** 29,34 ****
--- 31,37 ----
  #include <stdlib.h>
  #include <string.h>
  #include <ctype.h>
+ #include <stdint.h>

  #include "Command.h"
  #include "ksysguardd.h"
***************
*** 47,57 ****

        /* To calculate the loads we need to remember the tick values for each
        * load type. */
!       unsigned long userTicks;
!       unsigned long niceTicks;
!       unsigned long sysTicks;
!       unsigned long idleTicks;
!       unsigned long waitTicks;
  } CPULoadInfo;

  typedef struct {
--- 50,65 ----

        /* To calculate the loads we need to remember the tick values for each
        * load type. */
!   //  unsigned long userTicks;
!   //  unsigned long niceTicks;
!   //  unsigned long sysTicks;
!   //  unsigned long idleTicks;
!   //  unsigned long waitTicks;
!         uint64_t userTicks;
!       uint64_t niceTicks;
!       uint64_t sysTicks;
!       uint64_t idleTicks;
!       uint64_t waitTicks;
  } CPULoadInfo;

  typedef struct {
***************
*** 146,159 ****
   * Parses the total cpu status line from /proc/stat
   */
  static void updateCPULoad( const char* line, CPULoadInfo* load ) {
!       unsigned long currUserTicks, currSysTicks, currNiceTicks;
!       unsigned long currIdleTicks, currWaitTicks, totalTicks;

!       if(sscanf( line, "%*s %lu %lu %lu %lu %lu", &currUserTicks, &currNiceTicks,
                &currSysTicks, &currIdleTicks, &currWaitTicks ) != 5) {
          return;
      }
!
        totalTicks = ( currUserTicks - load->userTicks ) +
                ( currSysTicks - load->sysTicks ) +
                ( currNiceTicks - load->niceTicks ) +
--- 154,167 ----
   * Parses the total cpu status line from /proc/stat
   */
  static void updateCPULoad( const char* line, CPULoadInfo* load ) {
!       uint64_t currUserTicks, currSysTicks, currNiceTicks;
!       uint64_t currIdleTicks, currWaitTicks, totalTicks;

!         if(sscanf( line, "%*s %" SCNu64 " %" SCNu64 " %" SCNu64 " %" SCNu64 " %" SCNu64, &currUserTicks, &currNiceTicks,
                &currSysTicks, &currIdleTicks, &currWaitTicks ) != 5) {
          return;
      }
!
        totalTicks = ( currUserTicks - load->userTicks ) +
                ( currSysTicks - load->sysTicks ) +
                ( currNiceTicks - load->niceTicks ) +
***************