Making API for energy calculation, unable to "Set Parameters for certain walls to certain directions"

[allazaruszcheong_21]

Developing RevitAPI, calculating net energy transfer by a bulidng, it involves the directions of the walls, it works on a simple model, but not a more complicated real life model. Need help.

//Checking for SouthWest Facing Walls & Windows
bool isSouthWestFacing = IsSouthWestFacing(exteriorDirection);
if (isSouthWestFacing)
{
SouthWest_Wall_Lst.Add(WE);

inserts_0 = (WE as HostObject).FindInserts(true, true, true, true);

ParaSouthWestWall = WE.LookupParameter("SouthWest");
using (Transaction trans = new Transaction(doc, "ETTV_1"))
{
trans.Start();
ParaSouthWestWall.Set(1);

foreach (ElementId emtid in inserts_0)
{
Element emt = doc.GetElement(emtid);
emt.LookupParameter("SouthWest").Set(1);
}
trans.Commit();
}

}

the first error occurs when i try to set(1) the SpecialParameters "southwest" to a checkbox 

[allazaruszcheong_21]

Hi update, there were missing parameters under the Text header, i have added them as global parameters

these are no longer an issue however a new issue arose being that being at line 1591

this is the error that pops up.

Anybody help?

[ctm_mka]

First, Check that what is being dim'd as a wall, is actually a wall, and not null. Second, if it is a wall, try get parameter from the element (e) instead of the wall. 

[allazaruszcheong_21]

They are walls...

[ctm_mka]

apologies, let me rephrase that, when your code gets to line 1589, verify that wall is not null.