If you specify the keyword _ALL_ on the VAR statement and specify the OUT= option on the SOLVE statement, the following warning message will appear in the SAS log:

Warning: Output dataset variable '_#seidel' contains illegal characters. Variable is renamed '__seidel' in output dataset.

This warning message is produced because the keyword _ALL_ on the VAR statement surfaces the internal variable '_#seidel'. This variable is used in the internal computations by PROC MODEL, but it cannot be used in an assignment statement in the model program. The warning message can be safely ignored.