asp.net mvc - EntityReference can have no more than one related object -

i have 2 identical controller actions , 2 identical views (one has different javscript file it). 1 view works fine, other gets hung on ef error:

a relationship multiplicity constraint violation occurred: entityreference can have no more 1 related object, query returned more 1 related object. non-recoverable error. 

i understand error doesn't make sense in context, when 1 view works , 1 doesn't. here bit 2 views causing choke (it's nasty lets ignore now...):

<% var x = ((ienumerable<project.models.booth>)viewdata["booths"]).where(b => b.rownumber == && b.columnnumber == j && b.boothgroupid == item.id).firstordefault(); %>                          <%if ( x != null)                           { %>                             <td class="assigned" title="<%: x.boothnumber %> - <%: x.exhibitor.name %>" style="width:<%: item.width %>px; height:<%: item.height %>px;"></td>                         <%}                           else                           { %>                             <td style="width:<%: item.width %>px; height:<%: item.height %>px;"></td>                         <%} %> 

this controller action details view causes exception:

public actionresult details(int id)     {         var results = g in db.boothgroups                       g.planid == id                       select g;          viewdata["id"] = id;          var plan = (from p in db.plans                     p.id == id                     select p).firstordefault();          viewdata["imagepath"] = "/plans/" + plan.name.tostring().replace(" ", "").tolower() + "/" + plan.imagefilename;          var booths = b in db.booths                      b.planid == id                      select b;          viewdata["booths"] = booths;          return view(results);     } 

this controller action 1 works, there call populate drop down list viewdata, removing doesn't seem affect 1 view or other.

public actionresult editassignment(int id)     {         var results = g in db.boothgroups                       g.planid == id                       select g;          viewdata["id"] = id;          var plan = (from p in db.plans                     p.id == id                     select p).firstordefault();          viewdata["imagepath"] = "/plans/" + plan.name.tostring().replace(" ", "").tolower() + "/" + plan.imagefilename;          var exhibitors = e in db.exhibitors                          e.meetingcode == plan.meetingcode                          orderby e.name                          select e;          viewdata["exhibitors"] = new selectlist(exhibitors, "id", "name");          var booths = b in db.booths                      b.planid == id                      select b;          viewdata["booths"] = booths;          return view(results);     } 

i'm rather stumped this, insight appreciated.

the error doesn't seem indicate problem, think should enumerate queries first , see happens.

var results = (from g in db.boothgroups               g.planid == id               select g).tolist(); 

and

var booths = (from b in db.booths              b.planid == id              select b).tolist(); 

as is, passing objectquery view , can cause problems view rendering since objectcontext may not in state in when made query. check model objects , make sure not calling db within somewhere.