You're on the right track! Needs some work, though.
SoH ghuHmoH jIH!
means
"You're. The view screen warns!"
Klingon pronouns are absorbed by pronomial prefixes:
qaghuHmoH!
= "I warn you!"
You could also go with yIghuH! ("Be aware!"). Alternatively: yIqIm! ("Pay attention!")
The word toy'wI' means "servant". Somebody who serves something - a waiter, or server - is a jabwI'.
However, I'd recommend something like HablI' ("data transceiving device"). Maybe DaH pa'vamDaq QaptaH HablI'mey. ("Data transceiving devices are currently operating in this room.")
De'toy'wi' bochu'Ha'chugh SoH, De'wi'patloHwi' DuQeH ghaH!
You've clearly done your homework and made an honest attempt, but this means something like "If you (plural) shut of the data-servant, you (singular are), the computer system admin, he/she will be angry at you."
I'd recommend:
HablI' Dachu'Ha'chugh, De'wI' pat loHwI' DaQeHqu'moHbej.
= "If you deactivate a data transceiver, you will certainly make the computer system admin very angry."
Edit:
Some people have - quite fairly - asked for some sort of support to back up my claims. Unfortunately, it's a bit hard to source a translation; my source is my own knowledge of the language.
Instead, I figure I'll gloss my text, so that people can easily verify it for themselves.
yIghuH! = "Be aware!"
yI- = imperative verb prefix; used when the object is third-person singular, or when the subject/listener is singular and there is no object (as in this case)
ghuH = "prepare for, be alerted to" (defined on p.88 of The Klingon Dictionary)
HablI' Dachu'Ha'chugh, De'wI' pat loHwI' DaQeHqu'moHbej.
= "If you deactivate it, you will certainly anger the computer system administrator greatly."
HablI' = "data transceiving device" (defined on p.88 of The Klingon Dictionary)
Da- = verb prefix used when the subject is second-person singular and the object is third-person
chu'Ha' = chu' + -Ha' = "activate" + undo = "deactivate" (see for example the sentence yIchu'Ha' ("Disengage it!") on page 49 in The Klingon Dictionary)
-chugh = type-9 verb suffix: if (TKD §4.2.9)
Dachu'Ha'chugh = "if you (singular) deactivate it/him/her/them"
Klingon is Object-Verb-Subject, so HablI' Dachu'Ha'chugh means "If you deactivate a/the data transceiving device(s)"
De'wI' = "computer" (TKD p.85)
pat (TKD p.100; compare jolpat* ("transporter system") and **'ul pat mutlhwI' ("electrician, electric system assembler"))
loHwI' = loH + -wI' = "administer" (TKD p.94) + "one who does" = "administrator"
In Klingon, a sequence of nouns X Y Z means "the A pertaining to Y pertaining to X" (TKD §3.4 The noun-noun construction). So, De'wI' pat loHwI' = "computer system administrator".
Da- = verb prefix used when the subject is second-person singular and the object is third-person
QeH = "be angry" (TKD p.104)
-qu' = emphasis verb suffix rover (TKD §3.4)
-moH = type-4 verb suffix: cause (TKD §4.2.4)
-bej = type-6 verb suffix: definitely (TKD §4.2.6)
DaQeHqu'moHbej = "you certainly make her/him/it/them very angry"
So, De'wI' pat loHwI' DaQeHqu'moHbej means "you certainly anger the computer system administrator".