Based on a quick look at your image, there appears to be a railing with many holes at the upper left which is probably generating many, many polygons. Under the ArchiCAD Help menu, select ArchiCAD Downloads and download and install the Polygon Counting Tool
. Running this tool will tell you the polygon count of the elements in your project, which could be the source of your problem.
You should add a Signature to your Profile (click the Profile button near the top of this page) with your ArchiCAD version and operating system (see mine for an example) for more accurate help in this forum.