Modding tech question

[spoon]

If I have this in Facility.txt:

Name := Miners Guild I
Description := Large scale planet processor which mines minerals from the deepest layers.
Facility Group := Resource Extraction
Facility Family := 1
Roman Numeral := 1
Restrictions := None
Pic Num := 57
Cost Minerals := 1500
Cost Organics := 0
Cost Radioactives := 0
Number of Tech Req := 1
Tech Area Req 1 := Mining Guild
Tech Level Req 1 := 1
Number of Abilities := 1
Ability 1 Type := Resource Generation - Minerals
Ability 1 Descr := Mines 800 minerals each turn.
Ability 1 Val 1 := 800
Ability 1 Val 2 := 0

...And I have the following in TechArea.txt:

Name := Mining Guild
Group := Applied Science
Description := The ability to extract minerals
Maximum Level := 3
Level Cost := 50000
Start Level := 1
Raise Level := 0
Racial Area := 0
Unique Area := 0
Can Be Removed := True
Number of Tech Req := 0

Why do I get the error:
Unknown Value "Mining Guild" for tech area Req 1 in record "Miners Guild I"?

Thanks,
-Spoon