To avoid this, you should take extra attention from Alexis's blog

The quest for Hellforge within Act 4 will always drop certain runes. The quest can be used to pay for D2R Items a quick run through the various acts. The Countess, found at the end of the Forgotten Tower in Act 1's Black Marsh, is another good source of runes.Because the runes are a set rareness that ranges from the most commonly used (El) through to the most rare (Zod) and are frequently used to create the economy in Diablo 2. El Through Lem are generally considered to be low runes, Pul to Gul are generally regarded as mid runes, while Vex up to Zod are typically considered to be high runes. If you come across high or mid-level runes on your travels, be sure not to part with these runes in a hurry!

Runewords are among the most powerful items you can craft when playing Diablo 2: Resurrected, though they do take quite an amount of effort to accomplish. First, you must find the appropriate runes for the runeword, then you'll need the weapon, shield, or armor that will accept the runeword. The item must possess an exact number of sockets in order for the runewords to work, and the runewords must be inserted into the item that is socketed in the right order. Also, the item has to be simple (white) or magic (blue) or rare (yellow) and unique (gold), or set (green) items with the correct amount of sockets won't work with runewords.

To avoid this, you should take extra attention when making a runeword. Double-check and triple-check that the item's type to ensure it is correctsuch as, for instance, the Insight runeword is able to be made in staves or polearms, but not spears. Also, arrange the runes in the correct order prior to socketing them into the item.

There are a few intricacies with regards to buy diablo II resurrected items weapon and armor which you must be aware of. "Body armor" is only items that are worn on your torso. General "armor" includes shields, boots, gloves, helms, etc. Hammers can't be used with runewords meant for maces. "Melee weapons" don't include ranged weapons, like crossesbows or bows. Orbs are also not considered melee weapons.