Error: exceeded maximum number of selection set

[HayBale]

What causes the following error and how can I correct it?

Select objects:

Error: exceeded maximum number of selection set

This error occurs after using autolisp files a certain number of times. If I close the Autocad down and restart, it fixes the error , but only temporarily. Then after using lisp files again a certain number of times, I get the error again. Any help is appreciated.

 

[tendai1]

Your autolisp routines are not coded very well, i.e. refer to AutoCAD documentation on selection sets (ssget),
I quote,

"Selection sets consume AutoCAD temporary file slots, so AutoLISP is not permitted to have more than 128 open at one time. If this limit is reached, AutoCAD refuses to create any more selection sets and returns nil to all ssget calls. To close an unnecessary selection set variable, set it to nil."