That's not a problem. It just means you need more than one hash table, each represented by a unique item name as the key.
As far as spaces go, you can use underscores in the name and replace them when you display it to users. Or you might even want a 3rd for the "display name", so that you can use a shortname as the key.
For instance:
item_dmg_req:
item1=0
item2=100
item3=250
...
item_dmg_mult:
item1=1.0
item2=1.1
item3=1.2
....
item_displayname:
item1=Some Fancy Item Name
item2=Another Fancy Item Name
...
Alternatively, you could store this all in a single hash table by tokenizing the values together:
# mult,req,displayname
items:
item1=1.0,0,An Amazing Item
item2=1.1,100,Another Amazing Item
...
The latter might be more efficient on item lookups and take up less files on disk but you will have more scripting overhead in pulling out the specific values and updating individual fields.
If your data is read-only, or more often read than written, you'd get more bang for your buck from the 2nd setup, since pulling out specific values is only $gettok($hget(items,%itemname),N,44) (where N=1,2,3) and can be easily abstracted in an identifier. Updating individual fields can be abstracted but the process becomes less efficient (due to all the retokenization).