Of course you are. It's your dryer and you are responsible for ensuring it is vented properly.

You might ask some of the other owners if they have had those problems also. I feel though that you will be stuck paying the repairs as it is inside your unit.I understand how you must feel. I own my own unit too and have paid out much in repairs.  
You might run this by the association president and see if they will pay for the duct work. If not you may as well do it. It seems unfair but the inside of the unit is your responsibility.What happened was an oversight on someone's part. These things happen.Just remember that the inside of your unit is always your responsibility.

Was the dryer originally put in by the condo builder a previous owner?

We had two condos that when built over 5 years ago the dryer vents were covered over by the siding installer. They never vented out of the building. When we required the owners to clean their vents we discovered the error and when you mention fire hazard the builder came back on site and repaired them.

The are a some variables as to who pays. 
 
1. Governing documents - You have to read all of them to understand who is responsible for anything from your drywall outward. In most cases, it is the HOA who is responsible to pay for the cost of reconnecting the dryer duct work to vent properly to the exterior. As far as subsequent damages, that is an insurance settlement between the HOA's and your insurance company. 
 
2. Is the condominium building still under warranty? If so, then the builder has to resolve issue and negotiate a settlement for subsequent damages. 
 
Ultimately it is the builder's responsibility because they goofed. If the builder is still in business, the HOA approach them directly or through an attorney to repair and compensate you for subsequent damages. A lawsuit may have to happen. 
 
There are probably some I missed. Taking a lot of photographs is definitely in order. 
 

Check your Declaration for the definition and boundaries of a unit. The sub-floor may be a common element and not part of your unit. If so, the association is responsible to repair the sub-floor.  
 
Also check the definition of the limited common elements, and who is assigned responsibility for each limited common element. Try to find specific language for the duct, or at least general guidelines. 
 
The duct probably needs to be installed through the common elements and through the outer wall, so the association has to install it. 
 
You cannot collect insurance since this is not sudden or accidental damage.

because it is above the ceiling (not below) I am almost sure it would be the responsibility of the board /association /developer if there is one

Are you sure it NEVER was vented outside? 
 
 
 
The reason I ask is because this year I had my dryer vent cleaned. The HOA has made it mandatory every two years. Last time I did it on my own was 5 years ago.  
 
 
 
They discovered the dryer vent became disconnected in the ceiling. The elbow fell off. It is 15 years old. These things happen.  
 
 
 
Pretty scary though. I was venting my dryer into my ceiling for maybe up to 5 years. Yikes! And 10 of my neighbors were doing the same. Double Yikes! Good thing the Board had the wisdom to make this mandatory- otherwise folks would never get their vents cleaned, and would never had known they were posing a serious fire hazard to themselves and all their neighbors!  
 
 
 
It cost me $400 to get a dryer vent rerouted. I patched the ceiling myself.  
 
 
 
It was IN my unit, so I am responsible.  
 
 
 
The tech who rerouted my connection told me he did 10 others in my 90 unit complex himself that month. So apparently this is a pretty common thing. That is why I mention it.  
 
 
 
However, if the dryer vent was NEVER connected, and you can prove it....I believe you have a case that the HOA should pay for it. Is it worth the hassle for 400 bucks though?  
 
 
 
In my best advice, just get it fixed and move on.  
 
 
 
Up to you though.

HELP! Subfloor vents is/was not made right & it's coming apart into our units making us very sick... burning our eyes, throats & noses; neighbors are getting sick in their unit too. Doc are saying to go to toxicologists to determine what toxins are causing our health issues; the ducts are crumbling apart & we're are pulling out massive amounts of conrete debris & rust; we even had 2 raw sewage leaks into our ducts & common areas they refuse to replace the carpet that was covered in kah-kah & it went into the duct work too; the management co is beyond hope & derelict in their duties; who is responsible for the faulty air ducts? This is not only issues of property deterioration it's a health issues as we have found out many of the residents with the same issues have died from lung cancer (they never smoked) & many of us have serious ongoing issues believed to be from the cement inflitrating our condos. The dust burns our skin & covers everything regardless how often we clean the vents the debris keeps coming. Cement is not good & breaks down according to conditions moisture etc. INSPECTAPEDIA recommend sealing off subfloor ducts & rerouting ducts in a safe manner. Who is responsible for the ducts that we are finding also containing empty beer cans in vents units as well as many other areas.