big white space ??

hello , i have a problem in my css file regarding my sidebar .

i wanted 2 make it 100 % , but its only working in IE , in FF its not .. after searching the forum i found that i have to add this line :

padding: 20px 20px 100% 20px ;

its working for the 100% prob issue but now i have another prob its that i see a big white space .. you can see what i mean Here : Galicia

scrool down you will see what i mean …

also this is the code of my sidebar i’m using :

#sidebar {
position: relative;
float: left;
width: 158px;
background-color: #A5B2CE;
height: 50% ;
left: 0px;
padding: 20px 20px 100% 20px ;
text-align: left;
font-family: Arial;
color: #000;
font-size: 7.5pt;
line-height: 11pt;
text-transform: uppercase;
}

Any Idea ?