Many errors at .xsession-errors file

Dear Sirs,  
 I have knoppix 3.4 installed at my Hard Disk. These days I observed that 
one of my /home/username files (.xsession-errors) was very big and 
constantly increased. I looked inside and I found meny errors like bellow. 
Do you know why this errors are there. Any suggestion / solution ???  
  
 Best Regards  
 Mike Kranidis  
  
 ---------- QUOTE ----------  
 kdecore (KIconLoader): WARNING: Icon directory /usr/share/icons/hicolor/ 
group 48x48/stock/form not valid.  
 kdecore (KIconLoader): WARNING: Icon directory /usr/share/icons/hicolor/ 
group 48x48/stock/image not valid.  
 kdecore (KIconLoader): WARNING: Icon directory /usr/share/icons/hicolor/ 
group 48x48/stock/io not valid.  
 kdecore (KIconLoader): WARNING: Icon directory /usr/share/icons/hicolor/ 
group 48x48/stock/media not valid.  
 kdecore (KIconLoader): WARNING: Icon directory /usr/share/icons/hicolor/ 
group 48x48/stock/navigation not valid.  
 kdecore (KIconLoader): WARNING: Icon directory /usr/share/icons/hicolor/ 
group 48x48/stock/net not valid.  
 kdecore (KIconLoader): WARNING: Icon directory /usr/share/icons/hicolor/ 
group 48x48/stock/object not valid.  
 kdecore (KIconLoader): WARNING: Icon directory /usr/share/icons/hicolor/ 
group 48x48/stock/table not valid.  
 kdecore (KIconLoader): WARNING: Icon directory /usr/share/icons/hicolor/ 
group 48x48/stock/text not valid.  
  
 X Error: BadWindow (invalid Window parameter) 3  
 Major opcode: 3  
 Minor opcode: 0  
 Resource id: 0x260003f  
 X Error: BadDrawable (invalid Pixmap or Window parameter) 9  
 Major opcode: 147  
 Minor opcode: 3  
 Resource id: 0x260003f  
 X Error: BadWindow (invalid Window parameter) 3  
 Major opcode: 3  
 Minor opcode: 0  
 Resource id: 0x260003f  
 ---------- UNQUOTE ----------