Please go to EWP installation directory :\\C:\Program Files\erwin\\erwinMetadataManagement\conf\conf.properties file
Open the file conf.Properties using notepad editor and open the file and go to section of
# M_JAVA_OPTIONS
change line of
#M_JAVA_OPTIONS=
to
M_JAVA_OPTIONS=-Xmx8G ( or even 16GB/32 GB depends on how much Memory you can allocate on this machine)
Save the file
restart erwin Web Portal services from control panel | Services
Try import again