Syler Helix

Okay, So I have been in search for this answer for over 5 weeks. I can create any model in BLENDER which My models are second life clothings such as tank tops, dresses, etc. Which I am having a horrific time because here is my issue: :::::ISSUES:::::: I create a model in blender which for in this example, is a tank top. then I go to rig it and then i try to upload to second life. I am always having issues when using blender to upload to second life. I export as a .dae with avastar. the rig is perfectly fine. no issues untill i go to upload to second life. then i have issues. alot of times my mesh in preview mode in sl mesh upload looks all CRUMBLED and destroyed like a paper ball.. it just isnt my mesh i made ... what could be the issue? ALSO I HAD a friend tell me about hexagon. so i tried hexagon, and then i tried importing my .obj from hexagon to blender avastar for rigging and it worked!!! however i want to use blender is there a way of fixing blender? what is the problem!???