Download Link Problem or url link problem or Unexpeted 404 Error

hi

i have a site that is https://www.freen70themes.com”, this site is all about nokia n70 themes. the problem is that when i browse that site through index page all download link of each post is working properly like for example there is a Bmw Theme whose download link is https://freen70themes.com/Bmw-Theme(freen70themes.com).sis
it works fine.But when i browse these posts through categories download link doesn’t woks properly like the above example if i access the post which is BMW theme it show download link that is <a https://freen70themes.com/category/Bmw-Theme(freen70themes.com).sis”

which have the most disturbing thing that is the word ” category” in the link through which wordpress send me 404 page not found error. so how can i remove the category name.

any one have the experience can help me to solve that problem.

with best regards
Waqas Tasneem