ksh: 0403-031 The fork function failed. There is not enough memory available.

This is caused by page space full

you may use svmon to check memory usage

size inuse free pin virtual
memory 4014080 4011444 2636 1078804 3687826
pg space 2097152 1930847

work pers clnt other
pin 941274 0 0 137530
in use 2191120 2395 1817929

PageSize PoolSize inuse pgsp pin virtual
s 4 KB - 3671460 1930847 878420 3347842
m 64 KB - 21249 0 12524 21249

you may use the following command to change page space :

chps -s pp_size page_file.

Example :
To change the size of the myvg paging space, enter: chps -s4 myvg
This adds four logical partitions to the myvg paging space.